A face showing a visual representation of damage and or pain. Originally from the game doom, as more damage is taken the face becomes increasingly more pained and bloodied.
Man you're looking messed up, you have a real "Doom face" on.
The face that results from shaking your head back and forth wildly and taking a random picture somewhere in the middle. Typical doom faces feature incredibly distorted lips/cheeks, oddly bared teeth, and half-closed, crossed eyes that are rolling back into their sockets.
The ingredients of a good doom face? A camera, a mirror/camera-man, and an excess of boredom.