I had tendinitis in my elbow (of my plucking hand).
I've switched to playing with a pick (to alter the muscles used to pluck) which helped a lot. Now I vary between pick and fingers.
Also, my chiropractor showed me an interesting thing. The pain in my elbow shows up right where the tendons meet the elbow joint. But THAT is only the symptom, not the problem. The REAL problem, the underlying cause for the tendinitis is in muscles elsewhere.
She showed me points all along the muscles of my forearm and the back of my upper arm...and after digging in and massaging with her fingers, found the REAL source of the pain. The muscles on the top of my forearm (opposite the side of the tendon pain) were even more painful than the elbow! So were the muscles just above my elbow on the back of my upper arm!!!
She told me to massage those areas while stretching my hand out backwards (like against a wall or table). Those areas hurt WAY worse than my elbow (who knew? 'cause without massaging those areas I didn't even know they hurt under normal use). But get this...after putting up with this tendinitis in my elbow for over two months, after two weeks of massaging those other areas...my elbow doesn't hurt any more!!!
I stretch those muscles before I play and ice them down and massage them after gigs. No more tendinitis.
My Chiropractor told me that it's the muscle fatiguing and cramping up from using those groups of muscles without stretching them first that causes too much stress on the tendons...and therefore the pain shows up in my elbow, when the problem isn't really the elbow itself.
But not anymore!!!
She did recommend lightening up on my playing as much as I could. If you are experiencing pain in your wrist, then check out all the muscles in your arm and hand. Dig in with a couple of fingers of your good hand all along every muscle of your hand and arm and see if you don't find some extremely painful spots somewhere other than where you are experiencing the pain now. The source of your pain is not where you are feeling it right now. I guarantee it.
Use drugs or surgery as an absolute LAST resort. My regular doctor wanted to dope me up and recommended surgery if that didn't help. NO WAY! Unless you specifically injure an area (broken bone, sprains, etc.) the problem is coming from overusing muscles that aren't properly warmed up first and the pain typically shows up elsewhere. Think about that. You didn't injure it, right (fall on it, twist it, pull it from lifting)? It just kind of slowly came on from playing and now it won't go away, right? If you really think about it, chances are you noticed the pain long before now, but probably blew it off because it wasn't all that bad. Over time, it gets progressively worse (because you ignore it or don't do anything any differently). You overdid it with a muscle or group of muscles from playing (or from playing awkwardly using improper technique that put a strain on those muscles), but the symptom is showing up in your tendon(s). Medical doctors often want to treat the symptom when in fact the cause is typically something else entirely.
My son has ADHD. Doctors wanted to put him on drugs to treat the symptom (very first thing they recommended...and while effective, those drugs are really bad for your body). We changed his diet and it went away. Drugs and surgery are not always the answer, and in fact are more than likely never going to get to the root cause of your problem. Even if you get cortisone injections, or have surgery the problem will just keep coming back if you don't change what caused it in the first place. Worse, would be getting injections to help you deal with it, but you keep playing without warming up (thinking it's OK now) and actually make the problem worse, or you have surgery and then scar tissue causes even more problems. There is a place for drugs or surgery, but that should never be the first attempt at becoming well again and staying that way.
If you use your hands for a living (and I do as an artist and musician), there is no way in hell I'm letting anyone mess with my body (with drugs or surgery) without exhausting ALL other possible treatments first.
