My daughter has a grape fruit size scar from a recluse spider bight on her right leg.
The scar is smooth but has three or four different colors as it could just as easily have been a burn. How much porential is there to having this scar covered with a tattoo?

Have her talk to a tattoo artist in the area and see what they say. It depends on the size, color, texture, and thickness of the scar tissue.