I have a heart-shaped face and have a nice, delicate chin but I would like to have a...
In my practice, I have used Restylane only for the treatment of fine lines and wrinkles, not for facial augmentation. It sounds like a chin implant combined with fat injections may serve you best. Results of a chin implant are, of course, permanent as long as the chin implant is in place; the longevity of fat injections depends on how quickly the body reabsorbs the fat -- I would predict 3 months to a year.
Chin augmentation with structural fat grafting
My preference is to use structural fat grafting, as much as possible, to enhance facial features. In many cases, the need for a solid implant can be eliminated by the careful and meticulous grafting of a patient's own fat. While the incidence of complications with facial implants is not high, certain problems may develop which require implant removal including infection and implant migration. Bone resorption (bone loss) has also been reported below solid facial implants. Neither of these problems are an issue with structural fat grafting.