When I smile I get a double chin type thing with deep lines either side of my chin. It is also seen when I talk or just generally open my mouth. I am not overweight at all, about 5'1-5'2 and 44kgs, so it's not really a double chin, but I do have a round shaped face. Any suggestions on how to fix this? I know it's not a huge deal but it really bothers me and makes me hate my smile!