I parked in a makeshift layby today. There was only enough room for my car as some numpty had decided to fly-tip the smashed up remains of a chair (sturdy wooden frame and foam upholstery). Got back to the car and (

) forgot about the chair - couldn't see it as it was below my line of sight oevr the bonnet. Drove off and found myself beached by the damn thing.

I managed to get the car off and found this damage. The exhaust is not leaking at all, but I'd like to know if this is just paint that has been rubbed off or a special finish. Either way, if it was your car, what would you do? Leave it or paint something over the damage to guard against future corrosion?