For a round bite like this one, blot on the latex with a q-tip, as shown. Use a press-and-lift blotting motion rather than simply drawing on the circle.
Use a hair dryer to solidify the latex. This will take a minute or two for small areas of latex.
Cover the latex with black makeup, then brush a generous amount of red into the middle of the wound. Lightly brush over the black area with red. We aren't done with the bite just yet.