After countless tests and several doctors I finally gave up on knowing the cause of my PN and resigned myself to idiopathic.

One consolation was the last neurologist I visited, who was in my opinion the best around, in his late 60s, said that when he first started practicing 60% of neuropathy cases were idiopathic, nowdays that number is down to 35%.

Another hope this doctor gave me was that the majority of idiopathic cases disappear on their own with no lasting damage after a maximum of 20 months.
One can only hope...
This being dependent on ever increasing dosages of pain killers is getting old.