Just following up on this.... I've used all the concoctions I mentioned above and when my tendinitis is flared up, nothing seems to help except for not using my arm.

I will say though, that when it is feeling only minorly irritated that the menthol-based absorbine and its tingly feel seems make me forget about the pain.

In the most painful times, I have found DMSO used every other day to avoid skin irritation was better at, but not entirely effective at pain relief.