Sudden blistering at the corners of the mouth is considered to be herpes simplex. It is a skin disease caused by herpes simplex virus infection, with erythema, clustered blisters as the main clinical manifestation, with a certain degree of contagious, also known as rotten corners of the mouth. In the specific treatment can be anti-viral treatment, can take oral vaxilovir hydrochloride, acyclovir tablets, at the same time should try to avoid scratching, stimulation, etc.. Because the disease is easy to recur, so should be treated as early as possible in sufficient quantity, suffering from this disease to the regular hospital as soon as possible, after the clinician diagnosis is clear to give reasonable treatment.