We just learned about the line of the top of the lips called the Cupid's Bow.
Another part of the lip is the Vermillion Border.
Vermillion is actually a word that means red.
The vermillion border is the place where the lip skin changes from pink or red to the color of the rest of the face.
(from: wikipedia - vermillion Border)
Kid Facts - Blast from the past: Maxillary Canine