I'm suffering from a painful, blistering rash called shingles

Shingles occurs more commonly on the chest and back, but can involve the arms and legs. — Wikimedia Commons

Shingles is an infectious disease caused by a virus called varicella zoster – the same virus that causes chickenpox.

Shingles appears as a painful rash or blisters, similar to chickenpox, that most often occurs only in one area of your body.