Some cases of shingles are painful only on one side of the body and can last for a long time, but no rash appears all the time. Herpes zoster is actually a virus that is latent in the body and starts to reactivate when the body’s resistance decreases or after exertion, causing the onset of the disease. After activation, the virus travels up the nerves to the local skin, causing a rash and pain in the corresponding area. Sometimes, only the nerves are damaged and painful, but the virus does not invade the skin and cause a rash, so there is only pain and no rash at this time. However, after a period of incubation, the virus starts to reach the skin, and blisters and erythema appear on the skin. There is also a special type of herpes zoster, which we call dull or incomplete herpes zoster. The so-called dull or incomplete herpes zoster is a special type of herpes zoster where only pain occurs without a rash.