The Acne Scars & PIH Edit

Post-inflammatory hyperpigmentation (PIH) — the dark marks that linger long after a pimple has healed — is the #1 search in K-beauty forums. The honest truth: there is no single 'best' product. Fading PIH is a stack job, combining three mechanisms: tyrosinase inhibition (vitamin C, alpha arbutin), plasmin blocking (tranexamic acid), and gentle exfoliation (mandelic acid, azelaic acid) to speed cell turnover. Every pick on this list addresses one of those three mechanisms. Stack 2–3 of them, be patient (6–12 weeks), and use SPF religiously — because every bit of UV exposure undoes the work. Deeper acne scars (icepick, boxcar, rolling) are a different problem that topicals can't fix; those need professional resurfacing. But for flat brown or red marks, this is the stack.