I hate to say use the search function here, but search for tendonitis and tendonosis. Somebody had some good comments about which is which and how to treat them. I had it really bad in both elbows at the same time (no idea how it happened) and I couldn't grip or toss for a month or so. It's been on and off since then, but the unable to grip part was only during treatments. The treatments were physical therapy, no disc golf for 4-6 weeks, then try it, then more physical therapy, then shots, then disc golf. It was over the fall/winter for me, so wasn't horrible since I hadn't played in winter previously.
I still have aches in the elbows, but I play whenever I want and I have no grip issues (aside from normal ones like early release
There are some cremes and such that have gotten some play, but I don't know that I can say they did much for me. There is a new creme the Dr. can prescribe that's sort of like topical ibuprofin and helps to reduce the swelling of the tendons.
The Dr.s will tell you that tennis elbow is a repetitive stress injury, but when it pops up all of a sudden, it sounds more like an injury done at that time rather than repetitive stress - thus, I think tendonosis came into play for one person. it's not identified often.
Good luck and think positive. It might be the end of your season, but I don't believe the end of disc golf for you.