OMG, hope your recovery is a speedy on.
Several years ago my brother, a biker, looked at the prospect of never riding a bike again or as you mentioned playing the guitar again
This was after a firework at a family bonfire party went off wrong and hit my brother in the stomach, where it exploded as he put his hand over it to try and get it off him,
it took out his biking jacket a jumper a shirt and a t shirt plus alot of his skin on his stomach and his hand was extremly damaged. The hospital even considered removing three of his fingers as they thought the damage was too extensive!
After alot of healing and alot of determination he managed to keep his fingers and now still rides his motorbike and plays guitar.
So even if the hospital dont look to hopeful dont just take their word for it, be positive and you never know the outcome could be a good one