Unlike most of our skin, lips are "glabrous," which means they contain no oil glands. Without natural moisture, they're prone to dryness and flakes. Apply generous amounts of a lip balm
that contains an occlusive, like petrolatum—or choose pure solid coconut oil
, says Beverly Hills dermatologist Ava Shamban, MD, who uses it on her lips every night. Persistent flaking and redness could indicate a product or food allergy; consider an allergy test (common culprits include synthetic fragrances and citrus fruits).
Hyaluronic acid fillers, like Restylane and Juvéderm, plump thin lips for about six months. The same filler can be used to smooth vertical lines around the edges of the lips—or try a silicone-based makeup primer for a pain-free (but far more temporary) fix.