I have never heard of thyroid medications causing PN/SFN, but I have heard numerous people on the Sjogren's forum say that hypothyroidism itself can cause neuropathy. So have you considered that it is the condition, not the treatment, that may be your problem? This might be a good question for your next appointment with the rheumatologist or neurologist.

I'm not sure about your plan to just stop your medication for a week or so. I am NOT well educated on thyroid issues, but know there is something called a thyroid storm when levels get out of whack. But it could be when levels get too high, not too low. Either way, you should do some research about stopping (suddenly) first, for the best results.

I would also think that logically it would take much longer than a week or so to know if it will help. If you have nerve damage, then it could/would take months or more for nerves to heal and pain to go away. Just a thought.