1. What Temple Hollowing Is, and Why You Notice It Without Seeing It
The temple is the slightly recessed area at the side of the forehead, bounded by the tail of the eyebrow, the hairline and the outer rim of the eye socket. On a younger face it sits close to flat, so the outline of the upper face runs in one unbroken curve from the cheekbone to the hairline.
When that area loses volume, the curve breaks. A shadow appears at the side of the forehead, the bony rim of the eye socket becomes visible as a distinct ridge, and in leaner faces the muscle beneath or a surface vessel can begin to show through. People describe the result rather than the cause: they say they look tired, drawn or gaunt, or that they look older in a photograph taken from an angle than they do in a mirror.
The change goes unidentified for so long because of where you look. In a mirror you examine the middle of your face: the eyes, the nose, the mouth, the jaw. The temple sits at the outer edge of that field of attention, so the loss registers as an impression rather than a feature you can point at. It is one of the few aging changes most people feel clearly and describe accurately without ever locating.