Patients with chickenpox can have a rash all over their body, but they may also have a herpes in their mouth. The mouth is a mucous membrane, so if the herpes is easy to break, after breaking will form a small ulcer, there will be a significant sore throat. The sore throat will cause the pain to increase when the patient eats, sometimes affecting normal eating, so chickenpox patients should eat easy-to-digest food during the chickenpox period properly. When there is herpes in the mouth, eat lighter, non-irritating food, otherwise it will lead to increased sore throat. Patients with chickenpox can develop herpes and sore throat completely within the oral cavity. If the herpes and the sore throat appear and disappear at about the same time as the overall condition of chickenpox, it is basically clear that the herpes is caused by chickenpox. If the pattern of the rash, or the time of its appearance and disappearance, does not match the overall course of chickenpox, then other diseases should be considered.