Please don't ever hesitate to ask me any questions. For someone who has been around the block with this thing like everyone else, anyway I can help, I am happy to do it.
I was diagnosed by both exclusion with an EMG like you (to rule out neuropathy in major nerves), and through a skin biopsy. Very simple procedure. As I understand it, the biopsy is done to measure the peripheral nerve density(?--of those "small fiber" nerves closest to the skin) and compare it to that observed with normal "healthy" patients. What I thought was fascinating about this neurologist (had previously been to others) is how much he agrees with my Lyme doctor's theories about chronic inflammation and what causes it. Before I even had the EMG done, he DILIGENTLY listened to my history and complaints about my symptoms (asked questions my Lyme doctor had asked me at the onset--Constipation? IBS? Heel and foot pain? Facial and torso pain? Tingling? Numbness? Tinnitus? History of significant infections? etc. And I think the most significant similarity is that they share the belief that this neuropathy was brought on by previous or active infection (in my case, both EBV and Lyme).
I am currently considering the treatment options that have been proposed--oral steriods (Prednisone) or IGIV. All I know about the IGIV is that it is IV treatment that is very expensive, and I am not sure if BC/BS will cover it (and at what %). Since I just got diagnosed this past Friday, I have been scouring the Internet all weekend to try to learn as much about SFPN and IGIV treatment. I have heard that Prednisone (which I have never been on) can be problematic for some, so that causes me some heartburn, particularly with how many meds I am currently on. My neurologist also mentioned the obvious (plenty of Vitamin D--which I am taking already), and he mentioned another supplement I had never heard of before that is very good for neuropathies.
I have attached a great link here that gives you some good basic info on small fiber peripheral neuropathy and the biopsy procedure. Hope this helps. The madness of putting this puzzle together continues. Please note that this IS NOT my neuro (who is based in Annapolis, MD-this specialist is based in San Diego)