Unlike a pimple on your face, which makes itself apparent the moment you look in the mirror, acne on your shoulders or back can be sneaky — revealing itself when you’re lathering up in the shower or changing your clothes. Treating it can be challenging for the same reasons. How do you apply a pimple patch to a blemish that you can’t see and can barely reach? Some of the same ingredients, methods, and even products used to treat facial acne work for back acne but with some crucial adjustments.