The four stages of herpes zoster are: prodromal stage, outbreak stage, recovery stage, and postherpetic neuralgia stage. 1. Prodromal phase: when the body’s immunity is reduced due to various reasons (such as cold, fatigue, malnutrition, radiotherapy, etc.), the varicella zoster virus latent in the human body is activated and replicates in large quantities, resulting in systemic symptoms such as malaise, low-grade fever, headache, poor diet and other generalized symptoms, and in a few patients there will be burning and pain in the affected area of the skin, etc. This phase usually lasts for 1~5 days, or there is no obvious prodromal phase. This stage usually lasts 1~5 days, and there may be no obvious prodromal period. 2. Eruptive phase: after the antecedent phase, light red spots appear on the skin, and then there are clusters of rice grain to pea-sized papules that do not merge, and then the papules gradually become blisters with tense and shiny walls containing clarified liquids, surrounded by a red halo, and the skin between the blister clusters is normal; accompanied by obvious neuralgia. This stage usually lasts 1~3 weeks, and the neuralgia is more significant in the elderly, which can last 3~4 weeks. 3. Recovery period: blisters dry up, crust, fall off, leaving light red spots or pigmentation, about 2~4 weeks completely subside. 4. Postherpetic neuralgia period: Herpes zoster is often accompanied by neuralgia, but most of them recover completely after the lesions subside completely or within 1 month. A small number of patients due to untimely treatment, nerve damage is serious, even if the skin lesions completely subside, there is still persistent nerve pain. This stage can last for months or even years.