Are you talking about the bottom lip or the top lip or both?
There is a condition called "mouth rot". I have no idea if those things on the lips are a symptom. I suspect a trip to the vet is in order.
Just as a general comment, you shouldn't remove shed unless it seems to be causing a constriction around a limb (or tail). You can offer fingers to rub on, but don't actively pull. You can do damage that way.