You can do breathing excersizes. One that a tubist I know does is get a metronome and breath in and out as deep as you can, first in quarter notes, than eigth notes, etc. Also, work on percussion and piano.

That's a drag. I am sorry to hear that. I would go insane!!!!!!!!!!!!! I don't know if this will work in your condition, but here's my suggestion. Practice pronouncing the sounds "eeee" and "oooo". Over exaggerate your facial muscles when doing so. You should end on the "ooo" with your mouth in the shape like that when drinking froma straw. It really works the muscles. Do it in 5 minutes intervals. I do it in the car driving around town.

Sorry to hear about your jaw. To work on finger dexterity and precision, try picking up a Hanon book (first 20 exercises) and working on those at a piano until the wires come off (start at about 60 BPM and gradually work up to 120 BPM as you master the exercises at the slower tempos). If you do this on a regular basis (and I'd recommend doing it daily), you'll notice a huge difference in your time and dexterity when you go back to the saxophone. Best of luck!