Medium chemical peels used most often are the 30% to 35% TCA (trichloroacetic acid) peels and the straight 89% phenol peel. These are used to treat brown spots, uneven pigmentation, mild wrinkles and mild acne scars. Healing time is less than 7 days, and mild redness fades in 4 to 6 weeks. This popular peel can be repeated to get more improvement in deeper wrinkles.