I just stumbled on your post. I have small fiber neuropathy (SFN), and live with a great deal of discomfort over large portions of my skin. I have used diphenhydramine for many years and at times in large doses, i.e., 100mg at a time. I use it as a sleep aid. I would like to follow this post and see what sort of responses you get. At this point my questions would be 1) is there a correlation between diphenhydramine use and the onset of SFN, 2) If discontinuation of diphenhydramine might lessen or reverse the effects.

Good luck to you in your quest for relief, you are not alone.