Today I decided to pick back up my clarinet after a two year total hiatus due to exams. However, after about 10-15 minutes of play, when I put my clarinet down and relaxed my right hand, my thumb began twitching involuntarily and has continued to do so for about 20 minutes on and off depending on what I'm doing, it's even making typing a little more difficult. I tried to find a cause on the Internet, but all I could find was information on musical dystonia in other fingers, and even then it doesn't really line up with what my thumb is doing.
I'd like to add that I'm double jointed, so when I rest the clarinet on my thumb, it curls upwards rather than resting straight. I already have an existing issue with cracking my joints, most likely due to instrument playing combined with being double jointed, but the twitching thumb is rather disturbing and I don't know what to do to alleviate the twitching.