I doubt if it's at all possible to bring it back to its original new state Kat.
What you can do is to fill the damaged area with something like Araldite........ better still would be this ..................
http://www.amazon.co....ef=pd_sl_8vlm8ncdfj_e
It's made by Unibond, and it has the advantage of being heatproof.
You'd have to colour the repair with a touch-up paint, preferably a high-temperature product.



