If the border between jaw and neck has blurred, filling along the line is an option.
As age or sagging sets in, the edge of the jawline blurs. Hyaluronic acid placed along the jawbone sharpens that edge and creates a division between face and neck. Because it goes into the deep layer over bone it tends to last, and when sagging is severe, filling alone is not enough, so it is better considered together with a lifting treatment.
One session lasts twelve to twenty-four months, varying by product. It goes into a deep layer over the jawbone, so it is little affected by expression, and firmer products are often used to hold the shape, which also slows absorption. That makes it last relatively long.