Could you tell me what happens if someone has shingles and it goes untreated for a long time?

Protracted shingles : Shingles with or without treatment often resolves. Treatment does have its advantages, potentially diminishing the severity of complication such as post-herpetic neuralgia, which can be quite painful and sometime disabling. If shingles persists with or without treatment, it should be brought to the the attention of a doctor who will order some tests to evaluate for a immune deficiency syndrome.