Marks left behind: post-inflammatory hyperpigmentation
Why a spot, shave bump, or scratch can leave a dark mark for months on richly pigmented skin, and how to describe it accurately.
- Written by:
- Navelle Editorial Team
- Reviewed by:
- Navelle Clinical Reviewer
- Published:
- August 23, 2026
- Reviewed on:
- August 29, 2026
Post-inflammatory hyperpigmentation, often shortened to PIH, is the dark mark left after skin has been inflamed. Acne, eczema, folliculitis, shaving, waxing, insect bites, and even picking can trigger it. It is not a scar in the structural sense: the skin surface is usually intact, and the color comes from pigment that was deposited during healing.
Why it lasts longer on deeper skin
More active melanocytes mean more pigment released in response to inflammation. On lighter skin the same event may leave a pink mark that fades in weeks. On deeper skin it can leave a brown or slate-grey mark that lingers for many months.
What tends to help the situation, in general terms
- Calming whatever caused the inflammation, rather than treating the mark alone
- Reducing friction and picking, which restart the cycle
- Consistent sun and visible-light protection, because pigment darkens with exposure
- Patience measured in months, not weeks
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