Herpes orofacialis is a disease of the skin and mucous membranes caused by the herpes simplex virus, mainly in the corners of the mouth, and is usually triggered by cold, fever or fatigue. When a person is fatigued, depressed, stressed or anxious, the immune system decreases and the herpes virus that is latent in the body tends to multiply, causing herpes to appear at the corners of the mouth or mouth. It starts with a burning sensation, followed by this blistering eruption and crusting, and lasts about a week, and is prone to recurrence, so you can use acyclovir cream or take oral acyclovir. If there is a secondary bacterial infection, you can use some aureomycin cream as appropriate.