For scars and sores: Combine pink or green face tissue with corn syrup.  
For facial hair: Use the hair from an old stuffed toy or hairbrush and attach with double stick tape or fake eyelash adhesive.
For blood: Combine red food color and corn syrup. Later, dripping the blood where you want it to be, don't let the edges of the blood bedaub. Let the fake blood plenty of time to dry and be aware not to wipe  your face later on in the evening!
For gore and blood : Use red food color, corn syrup and chunky peanut butter.