Acne under the cheek is usually folliculitis or acne. The symptoms of both are similar, but the causes are different and the prognosis is different. 1. Folliculitis: mainly due to Staphylococcus aureus infection of hair follicles, resulting in papules and pustules on the skin, which can be easily cured with mupirocin ointment or fusidic acid ointment applied externally. 2. Acne: occurs in adolescents, which is usually called “acne”. “This is because after puberty, androgenic activity increases, promoting sebaceous secretion and pore blockage, coupled with Propionibacterium acnes infection, resulting in acne flare-ups. It can usually manifest as polymorphic lesions such as pimples, papules, pustules, and nodules. Treatment can be done with topical fusidic acid cream or clindamycin gel and oral isotretinoin soft capsules to inhibit sebaceous gland secretion and reduce pore blockage. For the scar left behind by acne, it can be treated by laser. For acne under the cheeks, whether it is folliculitis or acne, it is more important to develop healthy habits, eat a reasonable diet, stay up less, and eat less spicy, high-sugar, and high-fat foods while treating with medication.