One benefit of fillers is that some fillers are easier to reverse if the results are not quite what you or the doctor sought, versus other methods of lip augmentation. This is especially true of those made of HA or hyaluronic acid, which is the most common type. I have used the 'lastest and greatest' 3D imaging technology, including imaged my own face to judge accuracy and usefulness of the imaging. In my opinion it will never replace the artistic eye of the surgeon. This is because living tissue does not respond like the clay or stone that a sculptor has in hand to work with. By seeking consultations in your area, you will likely find a doctor you feel comfortable with based on your discussion with the doctor. Best of luck to you.
Your strategy is excellent in trying a filler before or even instead of committing to invasive surgery, such as chin implantation. The fact is, each person responds to fillers differently, which affects how long the filler lasts. Fillers are divided into temporary [several months or more], semi-permanent [months to years], and permanent [several years or more]. The basic 'HA' or hyaluronic acid filler is considered 'temporary', and may be a good choice because it is the world's most commonly used type and is considered the safest by many. You can easily obtain a free consultation from someone in aesthetic medicine or cosmetic surgery in your area to develop a treatment plan if this bothers you.
Exercise may decrease facial fat as well as body fat, and this may contribute to an aged appearance for some. Many note that sleeping on one side of the face may accelerate wrinkles and folds appearing to that side. You look your own stated age in your photo, not 50, but any uneven area often has many good solutions, some that you mentioned. You can easily obtain a free consultation from someone in aesthetic medicine or cosmetic surgery in your area to develop a treatment plan if this bothers you.