When they are ready to come out, the deer sneezes and out they come through the nasal passages.

The holes you see in antlers are also caused by Bot fly larve.

I guess if you were only born with one arm, the other arm wouldn't hurt you.
The same with deer, if you had worms in your nose all your life, you wouldn't even know that they were there. You would just get used to them being there.

They were probably checking for CWD.