Your first question:
Some drugs (HIV drugs and chemo) do recover if the patients use acetyl carnitine. These two families of drugs cause PN.
I have not seen studies on healing PN from Statins. (some people who come on these boards, have improved, others not.)
Drugs like Flagyl, some posters here are not showing improvements. Fluoroquinolones I have posted anecdotal information on my Subforum thread.
I have seen reports of improving alcoholic induced neuropathies with B vitamins, and diabetics are in the studies currently using
alpha lipoic acid and acetyl carnitine and benfotiamine (a form of B1).

Your skin biopsy results only shows a window of time when the biopsy is taken. It does not show what you had before, or what the future holds. The results are averages just like for blood testing. It will give an idea, but nothing definite.

I think you need to start that gluten free diet while you wait for results. If your culprit is gluten, you can see small improvements within a month.

You absolutely must read more and study up. Much of what you can do will have to come from YOU, and not doctors.
Check out the stickies on our Gluten forum for excellent links to help you. There have been many people here over the years with gluten induced neuropathies who have improved and moved on to the gluten free communities on the web.
There have been a handful of misdiagnosed MS patients too.

This site has a special section on gluten intolerance inducing neuropathy:
http://sites.google.com/site/jccglutenfree/