FOUND THIS BUT HAVE NEVER USED
Small saucepan or use 1 c. Glass Measuring cup in Micro
Red or brown water colors or make-up blush
One envelope unflavored Knox gelatin
Dissolve gelatin in 1/4c. cold water in a small saucepan, let set 1 minute, then continually stir over low heat until gelatin/water mix is clear. Allow to cool.
In the meantime, using a paintbrush, paint the shape of your scabs on your "victim" with corn syrup. Carefully cover the entire "scab" cornmeal. Let it set up for 2 full minutes, then lightly blow off the excess.
Carefully shade the scab with the make-up colors you have chosen. By now your gelatin mix should be cool, very carefully paint the "scab" with the mix, avoiding pressure so you don't ruin the cornmeal texturing. The gelatin will help seal your "scab" and prevent it from wearing off.