"I have tendonitis in the wrist and wonder if there is something that can help with that?"
Yes, cannabis can help with inflammation. I have had the same problem and of course doing all the normal suggested treatments is a good idea. In addition using a cannabis topical could really help with the pain and inflammation.
I would also use a high ratio CBD tincture, sub lingual spray or pill. This treatment for me 1-2x a day keeps inflammation down. I use a CBD:THC ratio of 18:1 or 20:1. There are different brands out there. The better ones use whole flower and are organic, without use of pesticides.
These treatments may not be the magic bullet but it certainly could help! Topicals can at the very least take pain away for a time, I love them! I always have one in my purse.
Hope this helps!