One would think with all your negative tests, that SFN would be excluded...but I DON'T think this is always the case. One of the things often not looked at during biopsy is the morphology, condition of the fibers. Just because you have normal fiber density, doesn't mean that the fibers them selves are in good condition and damage fibers can (and will) cause symptoms of SFN. Sadly, many pathologists don't check the condition of fibers, especially once they see density is normal. My first biopsy at Johns Hopkins showed exactly this...normal density yet segmented, tortuous, and swollen fibers, along with very patchy distribution. A year later another biopsy was done and the condition was worse. Let me also add that your symptoms are relatively new and therefore, you may not have noticeable findings (in regards to density) at this early stage. Did they give you the percentile of density? This is important as you may be on the low end (yet still in normal range) which would explain your symptoms at early stage.

So other then finding a pathologist to review your samples (which are typically saved/preserved) and assess the condition, I think you might also consider an MRI of the spine (thoracic and lumbar). Compression issues are a very common cause of neuropathy and it doesn't appear you have had this ruled out yet in the most common area that it occurs.

As for the face, is it possible you have candida? You have had numerous antibiotics, if I remember correctly (from the pneumonia) and candida is a very common cause of your facial symptoms, even on the tongue.

Otherwise, I still think the SVID could possibly be causing your facial symptoms...especially since I have experienced it myself and know those very findings on your MRI (just like mine) can cause those same symptoms. Those small nerve fibers in the face are greatly effected by those tiny vessels being ischemic...and you don't have to have lesions. At least it shouldn't be ruled out as the cause. of course, it could be an extension of the neuropathy, but I think it would be a bit more odd to see this much progression to the face when you don't even have positive findings on biopsy anywhere else (yet---but that may change in time). A consult with a vascular doctor would be helpful in regards to your facial issues.

Go slow on the Prednisone taper...it is not going to be fun coming off it and can take some time. Patience and going at your own pace is best.