GORE WARNING, IF YOU DIDN'T CHECK THE TITLE!!!

ALSO; THIS IS HUMAN/SOME REPTILES/MAMMAL BITES, NOT BUG BITES!

First, start with a very light skintone. Make it quite a bit lighter than the character's regular skin. This will come into play later by adding layers of color.

Secondly, take a reddish-brown and make a curved dotted line, each dot/notch where a tooth would go.

Take a plain red and put a line over the dots/notches, like a dot-to-dot book. Make sure to let the red go farther than the dots, but not by much.

Take the skintone(slightly darker is preferred) and redo the skin. Make sure to do it around and over the bite, and let the red bleed out.

Take a lighter red and line the mark. Be kind of random about it.

Next, take a pinkish-red and line the whole arc.

Redo the skintone, especially around the pink-red. Again, let the colors bleed into the skintone.

Lastly, for more detailed work, redo the red, since it probably was dulled by the skintones(If your markers are like mine)

And that's it! Go and draw all the bites you want, and stay safe!