The sudden appearance of a red hard pimple on the face may be related to the abnormal keratinization of follicular sebaceous gland ducts, the proliferation of Propionibacterium acnes, and lifestyle habits, etc. General treatment, medication, and physical therapy should be chosen according to the cause of the disease. 1. For those caused by abnormal keratinization of follicular sebaceous gland ducts, topical adapalene gel or oral retinoids such as viamin can be used as prescribed by the doctor; photodynamic therapy can be used to improve the keratinization of sebaceous gland ducts. 2. For those caused by Propionibacterium acnes, topical clindamycin gel or oral minocycline and other antibiotics can be used as prescribed by the doctor; photodynamic therapy, blue light treatment and other methods can be used to kill the germs. 3. For life habits caused by, should cultivate good habits, avoid staying up late, overwork, pay attention to regulate their emotions. It is recommended that people who suddenly have a red hard pimple on their face should consult a doctor in time to clarify the cause of the disease and carry out standardized treatment under the guidance of the doctor.