Surgeons often fill frown lines with fat to decrease the appearance of lines between the eyebrows. The grafts are either injections of fat or strips of fat, often harvested from skin left over after a face-lift.
Large grafts may absorb but smaller grafts are more likely to succeed and be permanent. Even if the graft absorbs there is usually some improvement due to the release of fibrous bands and scar tissue.
When fat is introduced under the skin, the fat closest to the surrounding tissue picks up a blood supply more quickly and so is likely to survive. Fat in the center of the graft may not get a new blood supply and may die (necrose) and eventually be converted to scar tissue. This may be lumpy.
Fat grafts are not new and in one form or another have been in use for over a hundred years.
