I, too have been diagnosed through skin biopsy, with SFN. It was a huge hassle getting the neurologist to test me. I have other health issues......but, my neuro doc.....soon to be my former neuro doc, tried to tell me it was all anxiety!! I insisted on testing and she found SFN. Are you taking gabapentin? It doesn't seem to do much for me....I'm also on Cymbalta. I will be going to a new neuro doc in October. Good luck to you, son. Kate