Some people often get small blisters around their lips or nostrils after a cold, fever, late night exertion, dense clusters, self-conscious burning and itching, and the wall of the blister breaks down to form a vesicular surface. We often hear people around us say that this is a “fire”, do not worry about it, it will heal itself. In some people, it can also occur around the external genitalia. According to the theory of Chinese medicine, this disease is really the evidence of fire and heat, or internal heat, or external heat, resulting in heat and toxicity, steaming the head and face or injecting the two yin, so it is called “hot sores” “fire blister”. In Western medicine, the disease is called herpes simplex and is thought to be caused by the human herpes simplex virus, which is divided into two types. Type I mainly infects non-genital areas above the waist, such as the head and face; Type II mainly infects areas below the waist, such as the external genitalia, anus and surrounding areas. Both type II can produce primary and recurrent infections. Most primary infections are acquired through direct contact with the patient, such as kissing or sexual intercourse, or indirectly through saliva-contaminated dishes. Type I is a non-sexual contact infection and primary infections occur mainly in young children within 5 years of age, with most infections having no clinical symptoms, and recurrent infections occur mostly in middle-aged and young patients. Type II usually occurs after puberty and is mostly transmitted through sexual intercourse. It is important to know that perioral herpes is not just a “fire”, but that it is caused by a virus and can be transmitted through direct contact, so it should also be treated actively to prevent recurrence and transmission to others around you.