The metal may not have stretched considering how small the crease is. The door post edge of the cowl is very strong because of the hinge supports so a small upset would not have moved it. The metal may have been pulled from the front of the cowl and will move back if the crease is kicked out.
Another thought. If you cut and weld you are going to have to skim coat with body filler anyway. Wire brush it down to bare metal and fill it and be done with it. It is relatively small and the only thing that would crack it is if the door is forced open again and that would dent the metal anyway.
