Begin by sketching a forearm, don't lean too heavily. Now add in an oval somewhere on the forearm, I did mine near the edge as this is probably the easiest.
Now add in arches along the top of the oval, don't lean too heavy here either. The arches face outwards.
Now add in more arches along the bottom and make these face the same way as the top set of arches.
If it helps mark approximately half way and sketch a line through.
Now start colouring from the centre out with a dark red pencil, lean light as you get towards the edge.
Now go over the bite in a red pencil, then go around the edge in a dark or light green pencil.
Now, add in some blood patches around the bite and add some green veins around it too.
Get a flesh coloured pencil and colour in the arm.
Now you're done! Add in a hand at the end of the arm if you want - I did but it didn't turn out too great :P
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