The most common cause of frequent blistering of the mouth is herpes simplex, a viral infection that should be treated with antiviral medications such as oral acyclovir or famciclovir and topical penciclovir ointment. In addition, vitamin or trace element deficiencies, digestive system diseases, history of tumors, history of radiation and chemotherapy, etc. may also cause herpes. In Chinese medicine, it’s called “fire” and is usually caused by liver fire. You can drink chrysanthemum tea, bitter tea, etc. You can also apply Chinese medicine to clear the heat in the upper jiao, such as Niuhuang Shangqing Pills, etc. At the same time, eat a light diet and avoid spicy and stimulating foods.