If your child has blisters on the upper lip, you need to pay attention to the following 3 causes: 1. The child may drink too little water, or vomiting, diarrhea, loss of too much water, which leads to this condition. 2. Pay attention to whether the child has some viral infections, such as some herpes virus infection, the child may have this blistering of the lips. 3. It is not due to vitamin deficiency, especially B vitamin deficiency, which may lead to this problem. The treatment for this situation is also based on the specific cause of the child. If the child is suffering from dehydration or drinking too little water, she should be given fluids in time. If it is due to vitamin deficiency, you need to pay attention to increase vegetables and fruits in the diet, and also pay attention to multivitamin supplementation. If the child is infected with the herpes simplex virus, pay attention to whether there is a fever, according to the situation after further examination before taking oral medication.