As we age and with sun exposure, skin and soft tissues lose flexibility and fullness, giving way to fine lines, deeper wrinkles and folds as well as shadows develop on the face.
Loss of fullness in the face is almost always due to fat atrophy. One then gets a skeletal or emaciated appearance. Lifestyle choices such as smoking and poor nutrition can accelerate these processes.
One can age gracefully, but there is nothing wrong with getting help to do this.