I Have Shingles On My Neck And Down Between My

I have shingles on my neck and down between my breasts. It has blistered and crusted. Now I have large red areas about 3 inches beyond shingles and covering one breast. These areas are very itchy and inflamed. Is this just going to keep spreading over my body? I know it usually follows nerve trunk but has not done so. How can I keep it from spreading?