A neurologist, who is a PN specialist, would Rx the proper meds.
A GP or PCP is very leery of taking on patients who say they need pain meds.
I've been taking Tramadol for 8 years, and along with Lyrica, have my PN
pain and symptoms pretty much under control. If he couldn't take Neurontin, why wasn't one (or more) of the varied anti-depressant meds used for PN tried?
There are over 75 meds currently Rx'd for PN because of different individual needs.
I think you need a PN specialist.