Dryness, redness and scaly skin are experienced if the product is initially used in
too high a concentration, or applied too often. Occasionally, these symptoms, if severe, may signal an allergy to benzoyl peroxide, and often include swelling, itching or tenderness. Dilute an over-the-counter, cream-based hydrocortisone cream with a little water to treat existing irritation. Allergy aside, the skin will adjust to benzoyl peroxide over a period of a few weeks.