Blisters on the lips can be caused by herpes simplex, fixed-type drug rash, mucous gland cysts, and other etiologies. Whether blisters on the lips can be punctured or not is related to the cause and severity of the disease. 1. Herpes simplex: caused by herpes simplex virus infection, it is not recommended to break the herpes. When the herpes is broken, the blisters containing the virus flow out, which can easily cause infection and may also aggravate the patient’s pain and other symptoms. 2. Fixed-type drug rash: it is an adverse reaction to drugs, often appearing in the same area, manifested as purplish-red erythema, which may be accompanied by blisters in severe cases. Erosion and oozing may appear after the blisters are broken. The blisters should not be broken, otherwise it is easy to cause infection. 3. Mucous gland cysts: If the blisters occur on the inner side of the lip mucosa, consider that they are related to mucous gland cysts. Mucous gland cyst is a blockage of the ducts of the glands and saliva retention. After going to the hospital, it can be treated by surgical incision. To summarize, there are different causes of lip blisters and different treatments. It is recommended to go to the hospital outpatient for examination to clarify the cause of the disease and then take the doctor’s advice into consideration.