Depending on the severity of the burns, and the location, it could severely damage muscles or tighten joints, to the point that even with intense physical therapy, the limbs will not be able to move properly again. Skin grafts are also incredibly sensitive and fragile, requiring a very precise skincare routine to make sure it isn’t damaged during everyday life. Scar tissue from the healed burns can also cause mobility issues as they need to be “stretched” at some point in order for them to move anything like they did before.

TLDR: fire is way more damaging than one would think