So long as your Master isn't in the room, and you don't show shame or fear in telling them that the bruises are consensual, they usually give a knowing nod. There are rare exceptions, and depending on your state they may be required by law to report the findings. Be aware of those requirements, and just tell them when asked that not only are they consensual bruises, it was dam fun getting them.

My girl had to go to the ER once shortly after we had played, and she had bruises. When asked, she just told them the truth. It's part of our sexual dynamic, and that yes they were consensual.