About seven out of ten teens suffer from red pimples, blackheads, and some other acne-like skin blemishes. “Acne is a disease that is completely treatable, but you have to be patient, as it often takes weeks before any noticeable improvement is seen,” says Lotus Engelen, vice president of the Berlin-based Federal Chamber of Pharmacists. Over-the-counter liquid preparations can help treat mild cases of acne. In serious cases, a dermatologist may prescribe topical or oral medications to the patient. Proper treatment of acne not only works to prevent scars, but also prevents its psychological damage, as adolescents with acne “at its…