What exactly causes deepening of the mental crease? (photos)

I've had some major changes to my face over the past months after a facial injury. The main differences, even though hard to see in photos, is slight sagging. My face went from a top heavy oval shape to a more boxy oval. I have watched as the tissues have dropped. This seems to have caused more bottom heavy face, a deepening of the mental crease, lengthening of my philtrum. I was wondering of saging of the midface/lower cheeks can cause influences on the lips, philtrum, and mental crease?