Some people are born with thinner lips than other people, but WE ALL develop thinning of the lips as we age. The upper lip continues to lengthen and the red lip becomes lower and less noticeable. Both lips also lose volume over time which causes less red lip to show as well as the annoying “lipstick lines” causing lipstick to run.
There are a number of very effective options for lip rejuvination including surgical as well as nonsurgical options. See my Lip Augmentation page for more information on adding volume or my Lip Lift page for information on surgical improvement of an elongated upper lip. Also check out my blog on Lip Lifts vs Lip Filler.