I have these two indentations below my lower lip. What's causing this? Should I get it fixed if it bothers me? (Photo)

Are you referring to the shadows on either side of your chin below the lower lip? Those are likely due to the shape of your orbicularis oris muscle (the lip muscle) that surrounds your mouth in that region. Some are stronger and more pronounced than others.  If it bothers you, you can certainly use some injectable filler to camouflage it.  Dental and jaw issues can also cause or exaggerate this appearance so you can ask your dentist about it at your next visit too.  Good luck! 

Hello dear
Thanks for the question and provided information as well. 
My recommendation for you is a personal consultation with a certified plastic surgeon to be able to make a complete evaluation and suggest the procedures that can fulfill your expectations and provide you with the best results.
Good luck :)