Lip injections refer to a cosmetic procedure in which filler is injected into your lips. Lip injections are an effective way to add fullness and volume to thin or uneven lips. The two most common lip injections are Juvederm and Restylane, both of which produce natural-looking results with minimal downtime and discomfort. For those who have deflated lips from age genetics, lip injections can be an excellent way to restore or create volume and fullness.