1. Complicated bacterial infections If the herpes zoster lesion occurs in a specific area, such as the eye, it may lead to serious consequences. If a bacterial infection develops secondary to herpes zoster, it can lead to full ophthalmoplegia or even meningitis, with sequelae such as vision loss, blindness, and facial paralysis. 2. Post-herpetic neuralgia Herpes zoster in the head is mostly found in the front part of the head, i.e. the first branch of the trigeminal nerve, which can cause hair loss and permanent scarring. Pain can persist for some time after the herpes zoster skin damage has healed. Some elderly patients with neuralgia can last for months or years, which can seriously affect sleep and emotions, and the heavier pain level and longer duration can lead to mental anxiety and depression. Herpes zoster can occur in the trigeminal nerve segment of the face. There is a nerve fiber in the trigeminal nerve, the ophthalmic nerve fiber, and some of the nerve fibers are distributed in the cornea and conjunctiva of the human eye as well as the whole eye. Patients may experience photophobia, lacrimation, eye pain, resulting in vision loss, or in severe cases, total uveitis leading to blindness. When the herpes virus infects the motor nerve fibers in the facial nerve, facial palsy can occur. The affected side of the eye cannot be closed, the affected side of the face has a dull expression, the corners of the mouth are skewed to the healthy side, and the patient cannot make blowing movements. 4. Triggering inner ear dysfunction Herpes zoster that occurs in the earwax and ear canal can cause symptoms of inner ear dysfunction. Patients show dizziness, nausea, vomiting, hearing impairment, nystagmus, etc. 5. Viral encephalitis and meningitis occur when the herpes virus invades the central nervous system, i.e., the brain parenchyma and meninges of the human body, from the nerve roots at the cremaster medulla upwards, manifesting as severe headache, jet-like vomiting, convulsions, limb convulsions, and life-threatening confusion and coma. When herpes virus invades visceral nerve fibers from the nerve roots at the crista medullaris to the body, it can cause acute gastroenteritis, cystitis, and prostatitis, manifesting as abdominal cramps, difficulty urinating, and urinary retention.