How about a picture?

Embrace the patina. It's only the first of many beauty marks to come. Maybe slightly sand it if it's sharp.

Without seeing a picture... Because stuns or bruises in marble can be quite deep, most likely the bruised area will need to be removed (ground away) and a filler used.
It is very difficult to fill/repair white marbles without it being visible. You need to decide if you would rather just fill it as is or remove the bruise and fill. A good repairman should have decent success removing the bruise and filling with filler.

novice-from-ct:

You need an experienced repairperson with an Invicon or Akiemi repair kit.