Some products (such as cleansers, foam, or lotions) may require a prescription. Check your product package to see if your form of this medication needs to be shaken. Apply benzoyl peroxide to the areas of your skin affected by acne. Avoid getting this medication into your eyes, inside your nose or mouth, or on any areas of broken skin since it may cause irritation. Use carefully, and avoid contact with hair, clothing, and furnishings. If you are using the liquid wash, cleansing pad, or cleanser bar, use it instead of soap once or twice a day. Wet the skin before applying, gently work up a lather for 10 to 20 seconds, and rinse thoroughly. Apply a small amount of the medication, gently rub into the area, and then shave.