Why Do the Marks Left by a Breakout Last So Long on Deeper Skin, and What Does the Research Actually Cover?

At Opuliss, we describe brightening as the look of a more even tone, and we do not promise to erase pigment.

What was the main prevention review actually measured on?

A 2025 systematic review pooled 369 cases of pigmentation left behind on skin of colour after the skin was irritated or injured. ³ Read its own account of where those cases came from: "Among 369 cases, 95% of the cases ( n = 352) were caused by laser therapy, 4% ( n = 16) from ultraviolet‐B (UVB) irradiation and 0.3% caused by chemical peels ( n = 1)". ³ Those three categories add up to all 369, which means not one case in it was caused by acne.

That review is good work and it answers its own question honestly. It is simply a different question from the one most readers arrive with. Its conclusion about laser-induced marks, quoted in full because the second half of it carries a hedge the first half does not, is that "only sunscreen consistently prevented the incidence of PIH; however, the severity of the ensuing PIH may be diminished with other measures". ³

So when you read that sunscreen is the one thing that prevents these marks, that finding comes from people whose pigment was caused by a laser.

Do two recent reviews of that same laser evidence agree?

A 2026 network meta-analysis looked at the same question, again for laser and energy-based treatments, and ranked the options against each other. It found that "Intradermal tranexamic acid (TXA), topical corticosteroids, topical vasoconstrictors, oral TXA, and epidermal cooling were significantly more effective in reducing PIH incidence compared with sunscreen monotherapy", and that sunscreen used on its own was not better than a placebo. ⁴ Its authors add their own brake: interpretation should stay cautious given how few trials there are and how small they were.

These two are not peers disagreeing. The earlier review pooled randomised trials alongside case reports and ran no meta-analysis; the later one took randomised trials only and combined them in a network meta-analysis. They still land in different places on the same narrow question, which is not a reason to stop using sun protection, sensible for many reasons beyond this one. It is a reason to be suspicious of anybody, including us, who tells you the answer here is settled.

On your actual question, have the trials recorded or enrolled your skin type?

There is research specifically on the marks acne leaves, and a 2025 scoping review went looking for it at the deepest skin tones. Its starting premise is blunt: "many clinical trials either fail to report FST data or do not include patients with FST V to VI". ² Its own conclusion, after looking, is that more data is needed on how well those treatments work at those skin types.

The pattern repeats in the laser review above. It reported skin type for 339 of its 369 cases, and the distribution runs "Fitzpatrick skin type (%) I 0 II 0 III 42.2 IV 53.7 V 4.1 VI 0 Total 339". ³ Read the last two entries: not a single participant at Fitzpatrick VI. That is a reported zero rather than an omission, which makes it worse, not better.

The advice is not reaching people either. In a survey of 51 people with skin of colour and acne-related marks at one Australian clinic, "Daily sunscreen use was inconsistent, with 39.2% applying occasionally (< 3 times/week) and only 33.3% applying daily", and fewer than a fifth knew sunscreen had any role in preventing them. ⁵ Its authors point at clinician counselling as the lever.

Why is the gap there?

It is not specific to this condition. Across the 215 of 246 United States dermatology trials that reported racial data, measured against United States census data, "Black/African Americans were most underrepresented and underrepresented even when accounting for prevalence rates". ⁶ In cosmetic dermatology, a survey of five journals from 2018 to 2023 reported: "Of 5,175 screened articles, 561 (10.84%) met inclusion criteria, and 214 (4.14%) provided FST data". ⁷ Read the two figures together: of the studies that did qualify, fewer than four in ten recorded skin type at all.

Part of the reason is the measuring instrument itself. Fitzpatrick wrote in 1988 that his scale was "created in 1975 for a specific need: to be able to classify persons with white skin in order to select the correct initial doses of ultraviolet A" for a psoriasis treatment. ⁸ That emphasis is his, not ours. Types V and VI were added later, for people with darker skin. ⁹ A current StatPearls chapter, written for clinicians planning laser treatment, states the consequence plainly: "this system has been recognized as ineffectual in certain populations, especially those with darker, non-Caucasian ethnic skin". ⁹

What does the regulator warn about?

A gap this size leaves room for products that promise what the evidence cannot. The US regulator is blunt about one end of this category: "Skin lightening products containing the ingredients hydroquinone or mercury may cause harm. The over-the-counter sale of these products is illegal in the U.S." ¹⁰ It also reports that it has received reports of serious side effects from hydroquinone, "rashes, facial swelling, and permanent skin discoloration (ochronosis)". ¹⁰ Note both halves of that: reports received rather than incidence measured, and a discolouration described as permanent.

Hydroquinone itself is not a villain, and pretending otherwise would be its own distortion. A clinical reference on melasma, a different pigmentation condition, records that "Hydroquinone is widely regarded as a highly effective depigmenting agent when used in supervised courses". ¹² What the evidence actually tracks is strength and length of use: a systematic review of ochronosis concludes that "hydroquinone in concentrations above 4% and in treatment courses longer than 3 months may be associated with new-onset ochronosis". ¹¹ Four percent is an ordinary prescription strength, so the threshold is about how long a course runs, not simply about who wrote it.

The most useful thing on that regulator's page is a checklist you can use in a shop: "Some illegal skin lightening products containing hydroquinone or mercury may not list these ingredients on the label. Avoid products with handmade labels, labels in languages other than English, or no label at all". ¹⁰ A product that hides what is in it is the problem, more than any single ingredient.

What can a dermatologist offer that we cannot?

Thin evidence is not the same as nothing to do, and it would be a poor piece that left you with only the gap. The same 2026 review this article opened with sets out what clinicians work with: "Treatment options include topical agents such as azelaic acid, retinoids, antioxidants, and hydroquinone, as well as systemic therapies such as isotretinoin, oral antibiotics, and oral tranexamic acid". ¹ It adds chemical peeling and energy based devices to that list, and calls photoprotection central throughout.

Opuliss sells none of these. Several are prescription only, the list above is what a clinical review reports rather than anything we recommend, and the hydroquinone entry carries every constraint set out in the section above. We are naming them because a piece that tells you the research has underserved you and then stops has done you no good at all.

What are the honest limits?

Skincare can genuinely improve how even and bright skin looks. It does not erase pigment, and it is not a treatment for any condition. Opuliss sells no sunscreen, so the measure most often recommended here is not one we can sell you either. And the honest summary is that the marks left by acne on the deepest skin are common, are distressing, and are still tested in trials that often do not record your skin type or enrol it. If your marks are spreading, very dark, or unchanged after months of consistent care, a dermatologist can tell you what is actually going on.

Frequently Asked Questions

References

1. Lopez-Estebaranz JL, Lopez-Pando M, Mitsunaga K. Practical therapeutic strategies for acne-induced hyperpigmentation across all skin types. Am J Clin Dermatol. 2026;27(4):697-707. PMID 42234395. doi.org/10.1007/s40257-026-01044-z
2. Smith CA, Hogeling M, Cheng CE. Treatment of acne-induced macular hyperpigmentation in Fitzpatrick skin types V to VI: a scoping review. J Drugs Dermatol. 2025;24(6):579-584. PMID 40465499. doi.org/10.36849/JDD.8703
3. Mar K, Maazi M, Khalid B, et al. Prevention of post-inflammatory hyperpigmentation in skin of colour: a systematic review. Australas J Dermatol. 2025;66(3):119-126. PMID 39953770. doi.org/10.1111/ajd.14432
4. Wongdama S, Yenyuwadee S, Li JB, et al. Interventions to prevent postinflammatory hyperpigmentation after laser and energy-based device treatments: a systematic review and network meta-analysis. Lasers Surg Med. 2026;58(3):157-168. PMID 41535730. doi.org/10.1002/lsm.70098
5. Hang X, Lim DS, Byrom L. Low sunscreen awareness and misconceptions in skin of colour with acne-related post-inflammatory hyperpigmentation: a cross-sectional study. Australas J Dermatol. 2026. PMID 41787948. doi.org/10.1111/ajd.70083
6. Mineroff J, Nguyen JK, Jagdeo J. Racial and ethnic underrepresentation in dermatology clinical trials. J Am Acad Dermatol. 2023;89(2):293-300. PMID 37062462. doi.org/10.1016/j.jaad.2023.04.011
7. Ehsan E, Truong-Balderas K, Ituarte BE, et al. Skin of color representation in cosmetic dermatology literature, 2018-2023. Arch Dermatol Res. 2025;317(1):458. PMID 39987416. doi.org/10.1007/s00403-024-03767-7
8. Fitzpatrick TB. The validity and practicality of sun-reactive skin types I through VI. Arch Dermatol. 1988;124(6):869-871. PMID 3377516. doi.org/10.1001/archderm.1988.01670060015008
9. Sharma AN, Patel BC. Laser Fitzpatrick skin type recommendations. In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2026. PMID 32491558. www.ncbi.nlm.nih.gov/books/NBK557626/
10. U.S. Food and Drug Administration. Skin product safety. Skin Facts! What you need to know about skin lightening products. Accessed 2 August 2026. fda.gov, Skin Product Safety
11. Ishack S, Lipner SR. Exogenous ochronosis associated with hydroquinone: a systematic review. Int J Dermatol. 2022;61(6):675-684. PMID 34486734. doi.org/10.1111/ijd.15878
12. Sathe NC, Launico MV. Melasma. In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2026. PMID 29083744. www.ncbi.nlm.nih.gov/books/NBK459271/

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