"Foot/lower leg", are you sure it's tendonitis? I've been dealing with a pretty severe case of plantars fasciitis the past couple of months, that ***** is he11!!! At times, it felt like a red-hot railroad spike was running from my heel, right up through my ankle. Stretching and a prescription strength anti-inflammatory (Diclofenac) helped, as did sleeping with a night-splint, but real relief came when I started using a
SofSole Plantars Fascia insert. Took a day or two to get used to them, but once I did, they were a miracle!
Not sure if this is helpful, hope it is, though!
Randy