so for potential fic writers what exactly does rei's nerve damage mean? nerve pain, numbness, no load bearing, can he move it, what would his physio be like, etc? i can't find a lot of resources but you seem to know what you're talking about :333 thank you!!
when you lose a nerve function, it's like severing the only bridge between two cliffs, cutting off communication completely between the brain and the limb. since rei's nerves are severed pretty high up, it is likely that most muscles innervation are impaired and he can barely move his arm, causing him to lose the ability to flex and extend his forearm, wrist and fingers. losing sensation to the whole limb is a given too.
just by severing the median nerve itself (that's a single nerve, and it's possible that he damaged more than one with that gunshot) would cause him to lose the ability to form a fist, to curl his fingers to hold a gun, and this is what left me in awe of the show's writing because it was so fucking brilliant. what use would rei be to the organization if he can't even hold a gun right and pull the trigger?
there's surgeries one could get to fix it -- nerve grafting, but it is costly, and i doubt rei would get it because that would defeat the purpose of him inflicting the injury on himself. physiotherapy is possible. most of the time it is done to prevent muscle wasting, but does little to improve on the nerve damages.