The phenomenon of pimples appearing on the corners of the mouth may be due to folliculitis in this area. If the hair follicles in this area are damaged to a certain extent, or due to local conditional pathogenic bacteria infection, or due to the patient's low immune function, etc., it may all lead to local inflammatory reactions.Of course, the pimples in this area may also be caused by a viral infection. Especially after being infected with the herpes simplex virus, it causes local herpes simplex to form. So at this time, the skin lesions may appear as localized erythema, and clustered blisters form on the basis of these erythema, accompanied by obvious pain at the same time.Of course, these pimples may also be soft tissue inflammation caused by local trauma, or contact dermatitis caused by local allergic reactions, etc.