Chicken pox and shingles (herpes zoster) are caused by a virus called varicella-zoster. Following a primary infection, the virus remains dormant at the ends of nerves (usually sensory nerve roots) for life. An individual’s immune response governs the likely symptoms as the body’s immunologic mechanisms suppress viral replication. It may reactivate if the immune mechanisms are compromised, which may occur with drugs, some illnesses, malnutrition or by the natural decline in immune function with aging. When the virus reactivates, it migrates along the nerve to the skin and causes the typical painful rash. After the illness has resolved, some patients continue to experience pain in the area of the rash, and this is called post-herpetic neuralgia. This is more commonly seen in the elderly (usually >60 years age). The use of antiviral drugs, if started within 2 days of the onset of rash, decreases the duration of symptoms and the likelihood of post-herpetic neuralgia. The pain is temporary but may occasionally, become chronic and require treatment. It can be treated by pain killers, local application of medicines or infiltration of the area with local anaesthetics.
Even though the blisters dry up in 7-10 days, the marks left behind can last for weeks. This is especially true if you pick at them. Please leave the area alone and they will heal fine over a period of few weeks. In case they remain persistent, you can consult a dermatologist as they can be improved upon with the use of a combination of lasers, dermabrasion or chemical peels.