I Had Shingles 4 Times Last Year In The Same

I had shingles 4 times last year in the same place each time on my back. I suffered nerve pain and my doc put me on 35mg daily dose of amitriptalyne, which worked beautifully. No pain and I sleep like a baby. She is now trying to reduce the dosage to 25mg and I am getting that horrible crawling sensation under the skin where the rash was? Not pain, exactly, but uncomfortable and distracting. I just wondered if this was normal? Thank you.