Fillers such as Versa, Belotero, RHA, and Restalyne are made of hyaluronic acid (HA).
When HA is injected, it absorbs water, and fills in the area that has lost it's volume.
Lip filler is done for those who desire larger, more defined lips. It can also provide relief to individual suffering from dry or chapped lips. 

Cheek filler helps increase volume and give more facial definition.