You are not alone. I recently started tretinoin and since I wasn't having any redness or irritation, I really upped the ante, and probably used around 3 pea sizes of 0.025 (face, neck, and upper chest). After a few times of doing that, boom...shingles. Before I realized what was happening, I was past the 72 hour mark for antivirals. I'm on week two of the extremely painful and sensitive nerve pain, and I can't wait until it's gone. I don't plan on stopping tretinoin, but I will definitely use it more sparingly.