Consider folliculitis, acne, herpes and so on. 1. Folliculitis: when hair follicles are damaged, they are easily infected with coagulase-positive Staphylococcus aureus or Malassezia furfur, which causes inflammation of hair follicles and their surrounding tissues. It is highly prevalent in people who usually have bad habits, such as scratching the skin often, not paying attention to personal hygiene, or have some chronic systemic diseases. 2. Acne: This is a chronic inflammatory skin disease of the sebaceous glands of the hair follicles with a high incidence in adolescents. The pathogenic factors are not entirely clear, but it is considered to have a relationship with heredity and androgen, and a large amount of sebum secretion will provide an anaerobic environment for Propionibacterium acnes inside the hair follicles and stimulate proliferation of keratinocytes at the hair follicle ducts and over-keratinization. 3. Herpes infections: Herpes simplex virus infection, herpes zoster virus infection, etc. will lead to skin erythema, and then soon appeared millet to soybean-sized pimples, and accompanied by skin pain. It is recommended to go to the hospital for further examination to find out the cause of the problem and follow the doctor’s instructions for treatment.