I would make sure that the flaking is from the injury and not from some sort of illness. If it is from the injury (which it most likely is, but I'd check just in case), some StressZyme and freshwater aquarium salt from your local pet store should do just fine to help the little guy feel better and relieve any stress he may be feeling. Check him frequently to make sure that no disease comes after the injury; sometimes fish can get wounds infected by microscopic things in the water, mostly fungal. The aquarium salt should, however, aid in prevention of that happening.
If you notice that your fish is purposely rubbing up against things in the tank trying to basically itch itself, and begins to develop spots that look like salt, THEN it's ich, if white fuzz grows on it, that's fungus. (pet stores sell treatments for these things if you happen to need them)