Recently, I sustained an injury in a sparring match - my fault for throwing out a suck-ass block for a round-house - which resulted in both my radius and ulna in my left arm breaking clean in two. I was admitted to the hospital around midnight, but the surgeon on call didn't come in until 7. The pressure from the bones severed several nerves in my arm, leaving me with a partially paralyzed left hand (I cannot make a complete fist). The lack of movement has caused severe muscle loss in my forearm, so that's where my question comes in:

What are some useful exercises for rebuilding muscle in my case? Should I be on any specific diet in order to aid in the process, and how often should I do these exercises?

Thankfully, I can still hit with my left hand - albeit far below full force - but hopefully, with physical therapy, I can at least gain some more strength.

Thanks in advanced!