Shingles, or herpes zoster, is a painful skin rash caused by the varicella zoster virus. It is a reactivation of the chickenpox virus, varicella, most commonly occurring in older adults and people who have weakened immune systems. Often people will develop a band or stripe of a rash that develops into painful blisters that fill with fluid, then crust over into a scab. Most people who get shingles will get better in 2 to 4 weeks.
However some people can develop postherpetic neuralgia (PHN), which is a nerve pain that persists after the shingles rash has cleared. The pain of PHN affects the area where the shingles rash had occurred and is usually a constant burning pain sensitive to even light touch.