For this image, I made a cast of the back of my head and neck and sculpted another face that fits tightly on the back of my skull.  When I started, I was thinking of the masks that some workers wear on the back of their heads while working in forests infested with man-eating tigers.  (Apparently, tigers prefer to attack people who are not looking at them, even metaphorically.) 
I originally saw this mask as a protective social device- ie, no one could sneak up on me at a party, but the final image has become more about a competition or balance between personalities- perhaps between a constructed self, and an actual self, which is only reflected anyway.