Full cheeks are classic signs of a youthful beautiful face. Sagging, sunken cheeks make your face look older and create a tired look.
When skin age it causes sagging of the facial skin. Gravity pulls the face skin down as we age and the malar fat pad that is attached to the cheek bone descents down and into the face. The effect is a sunken cheek on and below the mid face where the fat pad used to be.