If it's clearly a scratch from someone keying it or the like, it'll be covered under comprehensive and as such won't affect your premium. If it looks as though you could've scraped against something, it'll fall under collision. Collision payouts can increase premium. So can overall claims history. You can be subject for cancellation even if all claims are not-at-fault, if your insurance credit score are low enough and you file too many claims. Someone said uninsured may pay; IT WON'T. Unless you can prove the driver of a vehicle that hit you did not have insurance, this portion of the policy won't pay.
Yes, I do this for a living and deal w/ it daily.