Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Acne or acne vulgaris is a common human skin disease which is characterized by areas of skin with scaly red skin, comedones, papules, pustules, nodules, and sometimes scarring. Acne affects mostly skin with the densest population of sebaceous follicles, which include the face, the upper part of the chest, and the back. Severe...