What are these lines on the side of my chin called and can you use filler to smooth it out?

Hi Sunbaby,
The folds you noticed are called Marionette lines and filler can be an effective tool for smoothing out the area around the chin. I always recommend seeing a facial plastic surgeon for your dermal filler injections, as their expertise can be critical in sensitive nerve-dense areas of the face.

Hi, the lines that concern you are called Marionette Lines and labiomandibular fold. Volumizers with Hyaluronic acids (Teosyal) or biostimulators eg; Radiesse can effectively smooth out the area. 
Do consult a highly experienced physician to treat you, as this is a tricky area involving the dynamic movement of the mouth.