Some cowardly turd scratched my car..................

[CrownPrinceBandar]

and left. They had to have noticed they hit me because at one place the scratch (from headlight to wheel well) is down to the primer. Any advice on how to fix this without going the whole insurance route ($500 deductible). I basically want to stave off future corrosion and paint chipping.

I figure I could get matching touch-up paint at the Subaru dealership, but can I easily treat it afterwords to shore up the clearcoat?