There are other alternatives to simply consuming anti-seizure meds (which is what Gabapentin is). You've fallen off the end of your neurologist's flow chart and that's all they've got left.

There are a number of supplements that have studies on pubmed demonstrating their ability to help with neuropathic pain and or repair. Try searching on alpha-lipoic acid or l-carnitine.

Also there is one company (Winsantor) in phase 2 trials with a drug that stops neurodegeneration and causes nerves to regrow. You can find their research on pubmed also.