Closed mouth is clinically known as closed acne, if closed acne on the forehead, you can take medication, physical therapy and other treatments to improve. 1. Medication: If closed pimples appear on the forehead, patients can use topical retinoic acid drugs, which have the effect of anti-inflammatory and eliminating pimples, such as retinoic acid cream, tazarotene gel, etc., but this kind of drug has the risk of teratogenicity. 2. Physical therapy: patients can take photodynamic therapy to improve the closed pimples on the forehead; you can also irradiate the affected area with red and blue light, which can remove Propionibacterium acnes and inhibit sebum secretion. 3. Other treatments: Patients can also utilize an acne squeezer to squeeze out the pimples, and it is recommended to perform aseptic operation under the guidance of a doctor to avoid facial damage. Elimination of closed pimples on the forehead of the method is more, it is recommended that patients go to a regular hospital, with the doctor for standardized treatment. Drugs need to be used in accordance with medical advice.