Despite the promise of Thermage and other Laser, radiofrequency, IPL devices, etc., I find they rarely deliver what patients expect.
You might consider Mittleman pre-jowl implants, which are a type of chin implant which is flat in the chin, but has a "bump" in the area of transition between chin and jowl ("pre-jowl"). It nicely smooths the line of the jaw.
Another approach is a combination of very light lipo of the cheek combined with filler or fat injection into the "pre-jowl" area.
These procedures do not tighten the skin per se, but they give the jawline a uniform and youthful appearance. You might want to give this a temporary try by injecting Radiesse into the prejowl area. If you don't like the effect, it's OK, one can manually massage and flatten the filler to reduce the effect. If you like the effect, you might want to continue periodically reinjecting Radiesse or trying the Mittleman prejowl implant, or the combo of lipo with fat injection.