Whenever I've told people that I self-injure, I actually make it a point not to look into their face right when I tell them. It bothers me so much to see their expression change. Sometimes, I've just looked off to the left or the right until I feel comfortable looking at them again. It's easier to sit sideways to the person because then you don't feel obligated to look into their eyes and it gives them however long to recover from their surprise and have a more normal expression.