The most common skincare mistakes, according to dermatologists, are over exfoliating, sleeping in makeup, skipping sunscreen, layering too many active ingredients, skipping moisturizer and picking at pimples. Most of them damage the skin barrier, the protective outer layer that keeps skin calm. On lighter skin, that damage usually shows up as redness. On darker skin, it often leaves a dark mark that can take months to fade.

The American Academy of Dermatology says irritation from skin and hair products is one of the triggers for dark spots in medium and deep skin tones. In other words, the routine meant to help your glow may be the thing dimming it.

1. Are you exfoliating too much?

Probably, if you do it more than a few times a week. Dr. Marisa Garshick, a dermatologist in New York and New Jersey, says too much scrubbing or acid exfoliation can strip the barrier, leading to redness, breakouts and tiny tears in the skin, plus a higher risk of hyperpigmentation. Dermatologists suggest gently exfoliating no more than three times a week.

2. Do you sleep in your makeup?

Stop, even on tired nights. Dr. Mona Gohara of Yale School of Medicine says makeup, sweat and oil left overnight can clog pores and leave skin dull and irritated. The AAD adds that even makeup labeled noncomedogenic can cause acne if you sleep in it. If you are too exhausted to wash, a noncomedogenic makeup remover wipe is better than nothing.

3. Do you skip sunscreen because you have melanin?

This is the mistake that costs darker skin the most. Dr. Janiene Luke, a dermatologist in Loma Linda, California, says research shows darker skin is still vulnerable to sun damage, and that UV exposure worsens dark spots and melasma. The AAD recommends a tinted sunscreen with iron oxide to help prevent and fade dark spots, reapplied every two hours and after sweating or swimming. Gohara recommends a daily broad spectrum SPF 30 or higher, all year long, since UV rays pass through clouds and most windows.

4. Are you layering too many active ingredients?

Retinol, acid peel pads and vitamin C serums all have benefits, but using them together can overwhelm your skin. Garshick says stacking strong actives can cause irritation and even chemical burns. Use one active per night and watch how your skin responds.

5. Do you skip moisturizer because your skin is oily?

Oily skin still needs hydration. Without it, Garshick says, skin may produce even more oil or become sensitive because the barrier is compromised. A light lotion with ingredients like hyaluronic acid, glycerin or ceramides works.

6. Do you pop your pimples?

Picking pushes bacteria deeper and fuels inflammation. Luke says it can lead to scarring and discoloration, especially in darker skin that tends toward postinflammatory hyperpigmentation. A pimple patch protects the spot and keeps your fingers off it.

7. Do you switch products every week?

Product hopping irritates skin. The AAD says to give an acne treatment six to eight weeks before deciding it does not work, and to apply it across the whole breakout area, not just on individual spots.

8. Are you following TikTok skincare trends?

Gohara says what goes viral is not always safe and compares it to taking heart health advice from someone who is not a doctor. If a trend promises extreme overnight results, skip it.

9. Are you forgetting your neck and chest?

Luke says many people treat and protect their faces but stop at the jawline, which creates a visible difference over time. Give your neck and chest the same care, including sunscreen.

What else affects your skin?

Sleep and alcohol. Gohara says your skin repairs itself overnight, and even moderate drinking can break down collagen over time. As the weather cools, it is also a good time to adjust products, since what worked in your 20s may not work in your 40s. If dark spots, acne or irritation keep coming back, a dermatologist who has experience treating skin of color can help find the cause.