One of my fingers (right middle) was injured about eight months ago, and I think it's recovery since then has been interesting. The injury happened by my trying to get a rollup door latch unstuck, and when it suddenly became unstuck, my finger was violently slammed into some metal thing. I believe that this damaged the tendon on the back of my finger, and the injury was ascerbated by my not changing my usual activities, including playing the piano for 16 hours during the 4-day Tacoma Holiday Food and Gift Festival later that month. The symptoms were that I was unable to fully bend the finger, such as making a clenched fist. These symptoms were (and are) more pronounced after prolonged motionless of the finger, such as during a night's sleep. I had read that injured tendons can take 6 to 12 months to fully recover, and my injury seems to be following that pattern. I also read that the new tendon cells that are built after a tendon injury are not as elastic as the old cells, and need to "learn" how to become more flexible. (Sounds like people, too!) During the first three months after the injury I wore a soft splint on the finger to prevent excessive bending of it while playing the piano. Since around Jan. 1st, I haven't needed the splint, and perform stretching exercises with the finger and its muscles to unstiffen it. Fingers have no muscles that control the tendons, so the muscles in the back of the hand and the forearm that control the finger need to be massaged so that they aren't too stiff themselves, which helps the tendon by making it not need to stretch as much for the finger to bend. Gently sqeezing the sides of the fingertip also seems to help a bit. While engaging in activities that require the finger to not be in the clench-fist position, such as playing the piano or typing this blog, I use every opportunity to make a clenched fist, so that the finger won't stiffen up. At least once every 3 minutes seems to work now, and the finger is still slowly improving as the tiny new tendon cells become more flexible.
All of this without a visit to the doctor; God often chooses to heal the body all by Himself!