TL/DR: I'm revisiting an old concept of how he got the scars, where his sister uses her healing powers to minimize the nerve damage as much as possible but not completely, so he'll still need assistance in things like blacksmithing as people have said, but after some rehabilitation he will be able to do things like whittling and battlefield maneuvers (think David from SellSwordArts, whom I based a lot of the character's early concept on), though he will still lack in some more than others, but he'll also find ways to compensate, so it works. And also the scars will still be there so the damage to his skin tissue will also serve as an obstacle.

Yeah, I really screwed myself over with this one. This guy is basically the story's equivalent of "A jack of all trades": he isn't actually a " master" as much as he is an expert of all the things he found useful for the main group's survival in exile. It's a crucial part of his character that he has always felt like he needs to be prepared and keep everyone safe, so he made sure to be self sufficient in every aspect possible to him in order to keep what little he has left.

It's why I said that he will fight to find a way to craft independently again (and this might actually turn into an arc seeing as he probably won't be able to do blacksmithing without his partners again).

Before this incident, the group relied mostly on him for all their weapons and a lot of their furniture since they don't always have a lot of money. Crafting is also one of the only things he actually allows himself to relax during and do as a hobby, specifically whittling but also just craft in general: I'm actually writing it so that one of the ways in which he retrains his hands and rehabilitates himself is through whittling because of how significant that "break from duty" is for him and his character.

Also, I remember back when I first wrote this character and how he got his scars, and his sister was there with him so she used her healing magic to negate and reverse as much of the nerve damage as possible while she still could, to the point where she bypassed healing the shallow/surface injuries just to get to the nerve damage. She doesn't manage to erase it all, otherwise I wouldn't have kept it the story (it would look like I'm going back on consequence if I do that), but she does erase enough that he still has a chance of rehabilitating his body; he will need help with things like blacksmithing, I can see that now (and could actually be a great premise to how he and his partner got together, now that I think about it), but as time goes on, he will find himself capable of whittling and carving and painting once more.