I dinged the trunk lid for my car the other day - luckily just on the edge (also had a couple of spots on one of my splash shields). I use some paint that I mix according to ratio and dab it on with a tooth pick rather then a brush. They took about 3 applications to build up. I then sanded it level with 2000 on a stiff rubber block. Then I did the same with the clear coat. The spot is no longer visible after wet sand, again with 2000, then rubbed out by hand with Presta 1500 or Meguiar's #2.
I tried a small brush first and found the toothpick trick worked best (at least for me)