I guess you just have to tell him straight out that the pain you are experiencing is unbearable, and you feel you can no longer live in this fashion.

Ask him if there is a pain management specialist he can recommend or refer you to. There are a large number of different pain medications available, you have hardly scratched the surface with the things you have tried.

The only other option might be a neurologist who specializes in treating SFN - but that's a pretty rare thing.

As far as the medications, unfortunately there are side effects to just about everything. At some point we all have to decide what level of side effects we are willing to live with in order to get some pain relief.