I havent had skin biopsy cause all the NCS/EMG's showed the damage -and since they were (and still are concerned) about amyloid (and vasilitis back when done) had the sural nerve.... it showed the exact type of damage - and if its any consulation tjb - the site where they cut the nerve (about two inches long - out of the back of my calf) - had shooting electrical pains for about 4 years - but now I can touch the scar and it doesnt hurt any more... sorry yours got infected - mine healed in about two weeks but wasnt receiving any treatments at that point to interfer with healing... I was on IVIG last year, and my doc wants to start weekly treatments again - but I have to go thru more amyloid testing first (cardiac and GI now)... the IVIG I did notice helped with energy - hope it helps you!