For many puppies, all it takes is the owner "YIPING" when puppy teeth touch human skin for them to stop this behavior. Give a "YIPE!!!" and stop the game for about 15 minutes...after you've had to yipe to get pup to take teeth off you. That's what another puppy would do, and it helps the puppy understand. This sound needs to be what a puppy would do when the idea is "Ouch! That Hurts! I don't like it! Stop it right now!"
In the litter, that offended puppy would then retaliate in some way, or refuse to play with the rough puppy for awhile. Some puppies have strong predatory instincts that are overstimulated when a person yipes, and for these puppies this would then not be an appropriate method.
