Over the years I've watched many people come on boards with this same issue.
"My doctor doesn't care".

I think that doctors know they cannot fix PN, so they are not motivated in most cases to do anything. They don't understand that :

1) finding a cause is important. If you have autoimmune neuropathy you can
try IVIG, or look at Gluten free life to help with it.
If you have ingested a toxin, you need to know what it was, to avoid.
If you have thyroid issues, or glucose resistance, you can fix that.

2) You can heal. You can try some of the nutritional supports suggested here.
You can have a MMA test to see if you are absorbing and utilizing B12. You can take B12 yourself...it is over the counter.
Other nutrients help nerves repair themselves. The peripheral nervous system is capable of that regeneration. But you won't hear doctors suggest this simple method because they weren't taught that in school.
Even Dr. Latov has put in his book erroneous information where nutrients were suggested. That is indicative at how little they think of it.

So getting a good diagnosis is important. But once you have that, traditional medicine has little more to offer. Strong drugs with heavy side effects are offered to "help", but they most often don't..they just create more problems.
People with severe pain issues, are deserving of adequate pain management, but many doctors ignore that too (here is where testing is very helpful in proving your pain).