Like you I have suffered for many years with the pain of PN and after a neurologist did EMG testing and a nerve biopsy he told me that I have SFN with autonomic problems and LFN. It seems that the EMG test results indicated LFN. That might be worth talking to your doctor about. I get the impression that neurologists do EMG testing quite frequently.

I have been diagnosed with idiopathic LFN only. I do not have it in my thighs. I have it below knees to toes, and below elbows to fingers. Balance is main issue with feet, and I can’t hop, skip, run, jump, squat or climb, but was able to learn to walk again after my sudden attack. My knees don’t seem to connect the bottom and top parts of the leg well. I don’t have reflex reactions when hit in knees and elbows with the hammer. My hand gripping and holding things are challenging. When Neurologists start at my toes/fingers and prick me with a pin, I don’t really start feeling the pricks until they get to over my ankles/wrists or a little further past that. But i normally have full sensation by the time they get up to my knees/elbows. We all have different variations though, these are just what I have with LFN. Regardless of those external tests and EMG tests for my LFN, I get the humming and internal vibrations feeling in my thighs sometimes, but not constant like it is below the knees and in feet, which are where I have the nerve pain that Gabapentin helps. That’s just my experience anyway, I hope you get to ask your doctor soon.