Forehead and chin acne is usually referred to as Acne vulgaris, which may be related to factors such as exuberant secretion of androgens, infection by Propionibacterium acnes, and abnormal keratinization of the cells around the hair follicles. 1. Excessive secretion of androgens: Acne vulgaris is caused by excessive secretion of androgens and stimulation of sebaceous glands to increase secretion. Sebum mixed with shed epidermal tissues clogs the pores, leading to acne attacks, resulting in the appearance of pimples and pustules on the face, which is the manifestation of acne vulgaris. 2. Propionibacterium acnes infection: Due to the excessive proliferation of Propionibacterium acnes, inflammation of the hair follicles can occur. Papules, pustules, nodules, abscesses and other manifestations appear, and patients thus have the symptoms of Acne vulgaris. 3. Abnormal keratinization of perifollicular cells: Due to abnormal keratinization of hair follicles, the diameter of hair follicles becomes smaller, resulting in the inability to discharge sebum and the formation of acne vulgaris. There are many factors that can lead to acne vulgaris, so patients are advised to go to the hospital and consult a doctor.