Postherpetic neuralgia is one of the common sequelae of herpes zoster, mainly refers to the pain in the area after the herpes zoster rash has healed, with the following pain characteristics: 1. spontaneous pain: the pain will continue to occur spontaneously whether the patient exercises or not; 2. skin-triggered pain: the area where the rash once occurred can be triggered by touch or hot or cold stimulation to cause a severe attack of pain; 3. abnormal sensation: including ant The pain level of postherpetic neuralgia is quite intense and can reach the highest pain level, which is very painful for the patient and difficult to treat, and the pain occurs at night, causing a greater impact on sleep.