not sure how to fix this

I’ve had this issue on two of mine. “Front hump” is where the metal was pulled out of shape with the mounting screw. Don’t replicate it. The basic shape of the door skin can be made by pushing sheet down over a pipe to create the curve. Weld that new piece in and redrill for mounting. Any sheet metal you buy from the big box stores will be a much harder alloy. It doesn’t shape as easily but it is much stronger.

Look at classic industries for the mirror reinforcements. They bolt into that area from inside the door and give much needed strength. Looking at the photo it looks like you might be able to use the reinforcement without any welding and grinding.