Why Do Pimples Leave Dark Spots—Even If You Don’t Pop Them? We Asked a Dermatologist

Welcome to Ask a Derm, a series from SELF in which board-certified dermatologists answer your pressing questions about skin, hair, and nail health. For this installment, we tapped Susan C. Taylor, MD, the Bernett L. Johnson Jr. Endowed Professor of Dermatology and the vice chair for diversity, equity, and inclusion for the department of dermatology at the University of Pennsylvania’s Perelman School of Medicine. Her specialties include hair loss, cosmetic dermatology, hyperpigmentation, and skin of color.

One of the golden rules of skin care: Never pop your pimples. Of course, it’s tough advice to follow if that angry bump is just sitting there, taunting you—and even harder when you do leave it alone and still end up with a hard-to-ignore dark spot.

In case you didn’t know, picking your acne causes trauma to your skin, which can lead to scarring and hyperpigmentation. That’s why pretty much every derm out there will beg you to keep your hands (and extraction tools) off your face. If you’re anything like me, though, you know from experience that leaving your pimples alone isn’t a foolproof solution: Even when I summon the willpower to let a zit run its course, I’m sometimes still left with a flat red or brown mark in its place. To figure out why this happens, I called in the help of a pro.

Basically, the buildup—of excess oil, dead skin cells, and sometimes bacteria—that causes acne can trigger an inflammatory response, Susan C. Taylor, MD, professor of dermatology at the University of Pennsylvania’s Perelman School of Medicine, tells SELF. During this process, your body releases pigment-producing melanocytes (the cells responsible for your skin’s color) to protect the affected area, Dr. Taylor says.

Thanks to this awesome immune response, you may notice smaller, surface-level blemishes like whiteheads and blackheads resolve on their own—without leaving a mark. But let’s say you’re dealing with more severe inflammation (from angrier, deeper cystic acne that has lingered for months, or even a nasty bug bite). In that case, your body might overreact and pump out lots of (and sometimes too much) protective melanin. “This can cause post-inflammatory hyperpigmentation,” Dr. Taylor explains—a.k.a. brownish or blue-gray spots that remain even after the blemish has healed.