if you sand aluminum, it never gets smooth unless you have the proper stuff. sand paper dont work.
if you try to paint it with some high temp stuff, it will never match since the aluminum isnt painted it almost like a dye on it.

if you cant afford a new one, and its really only a cosmetic thing id say just drive with it like that. it wont hurt anything.

put some tie wraps on the head next time to help revent this in the future.