I agree that this is the work for a professional. Short of that I would say a good starting place is negatives. The good thing about negatives is they are pretty safe if done within reason. Just draw back a light weight bow to anchor and slowly lower your draw. Do that a few times and you'll develop your strength back. Be sure to warm up of course - rotations, stretches, etc. and start slow and light. This method is solid for many things, pull ups, bench, etc, but we're just talking bows here. Again, whatever PT help you can get is ideal, but I wouldn't be surprised if they gave the green light for some reasonable negatives routine. Good luck!