so I only read the first part of this thread.

I have two comments now...

1) Allopurinol is one of the drugs that can cause PN. This is not common but it does happen and is documented on MedLine.

2) If you switch to benfotiamine--which is a more potent type of thiamine you may see an improvement. This has become more affordable recently and if you get it at iherb.com it is not as expensive as it was (but it is more than plain thiamine).

300mg a day to start is best. I use Doctor's Best brand.

It is possible that your issues are from something else.
Other drugs cause PN --some quickly.
Cipro/Levaquin
Metronidazole
statins for cholesterol

And these may be the cause or additive.

I'll be back in a week and can devote more time and thought then. See ya.