Sunken cheeks occur when the face loses volume and support, especially in the mid-face. This can give a more tired, worn-out, or older appearance, even in people with otherwise good skin quality.

The condition develops gradually and is often associated with the loss of fat, collagen and elastin in the face.

Why cheeks lose volume
Volume loss in the cheeks is usually caused by a combination of:

Natural aging and reduced collagen production
Loss of subcutaneous fat over time
Genetic factors
Weight loss or hormonal changes
Prolonged sun exposure
When the support structure weakens, the contours of the face can change and the cheeks may appear more hollow.

Sunken cheeks can contribute to:
Less defined facial contour
More prominent lines around the nose and mouth
A tired or tense expression
Changed balance in facial proportions