Acne on forehead and cheeks is usually caused by acne, which is generally related to genetic factors, changes in androgen levels, keratinization of sebaceous gland ducts, and propagation of Propionibacterium acnes. 1. Genetic factors: Acne has a certain hereditary nature, if parents suffer from the affected area, the chance of the next generation suffering from the disease may increase. 2. Changes in hormone levels: If the level of androgen in the body is high, or if there is an imbalance between the levels of estrogen and androgen, this may increase the production of sebum, leading to a higher chance of suffering from acne. 3. Keratinization of sebaceous gland ducts: If the sebaceous gland ducts are keratinized, the hair follicles will become smaller and clogged, which may lead to sebum not being able to be discharged out of the body, increasing the chance of suffering from the disease. 4. Propionibacterium acnes reproduction: Propionibacterium acnes can activate keratin, causing it to form cells, which may induce acne if Propionibacterium acnes overpopulates. For patients with acne on forehead and cheeks, it is recommended to go to a regular hospital for examination to clarify the cause of the disease.