I used to use a tens on my back for L3-5 nerve damage, sciatica and more. Before a huge surgery, and a lengthy recovery to correct some issues, my Tens was one of my best friends and a big part of an arsenal of things -creams, roll-on's, heat, ice, PT, massage and prescription pain meds- I used to combat pain.

I can't use one any longer as I had a spinal cord stimulator implanted to finally help diminish the pain from what they call “failed lumbar surgery syndrome”. But the stimulator is very much like a Tens in that it electrically disrupts the pain with a similar electrical current. So, I still sort of have one-its just inside!

The best to use I go on my p therapist advice is bifreeze or stop pain the stop pain is wonderful for back pain and knees hope this helps.

I have severe pain in my feet and hands. My RA doc orders a special formulation of Diclofenac (5%) & Tetracaine (2%) cream. Works great. Applied up to 4 miles daily.
OTC Voltaren is a weak 1% Diclofenac but there is a RX strength that is 3%.
there are also some formulation of pain reliever creams.

Talk to your RA doc and your Pharmacist.

Zoltarin is really good for RA they just started putting it over the counter instead of a prescription