Hi Aussie, Seeing all your blood & other tests all show negative, but you continue to improve as time goes on, then its probably fair to say that whatever has caused your nerve damage is well gone now buy the looks of it, may have been some sort a virus perhaps ??? that has made your immune system go hay wire, causing damage to your small nerves, as you would know we can get some really weird viral strains these days that can become that serious to cause some people to be hospitalized, compared to years ago it was just the same old flue symptoms every year, but i think that has defiantly changed over the years.

Increased burning is a typical sign of small nerve repair, thats what i went through whilst healing, there's no set pattern they can start burning at any old time, and the flushing could be your systems response to when your burning starts which would cause anyone to become anxious.
I hope it all settles down for you soon.

Brian