Is there such thing as nerve replacement, nerve therapy, or nerve graphting? this is very important, please someone tell me there is!

Maybe: Depending on what you are talking about, nerve grafting may be possible.

Yes, yes, and yes: It is possible to replace or graft a nerve that is damaged. Very careful evaluations need to be done concerning appropriate technique. Nerve therapy is very important. Just using the nerve will help with recovery, but should be under supervision with a trained therapist.