Brass player here. You can tear the orbicularis oris (muscle around your lips) by using improper technique, which easily creeps in if you’re overdoing it by playing beyond your endurance. I’ve had this happen, but was inspired to work toward recovery after reading about Colin Williams (trombone).

Also, focal dystonia. In sports it’s called the “yips”. This is a neurological issue where you cease to be able to perform a fine motor action, such as forming your embouchure, pressing your instrument’s keys with speed and coordination, etc. This has ended the careers of numerous virtuosos such as Warren Deck (tuba) and Phil Smith (trumpet) due to their inability to form their embouchure, as well as oboists and flutists due to their inability to press the correct keys.

These two problems turn musicians’ lives inside out.