Filler or 2nd surgery? (Photo)

When the skin drapes over the jawline into the neck, lipo alone, even with a skin tightening modality, is not enough to get better definition. Injected fillers have no roll in getting better definition. Parenthetically, there is a procedure called Y-lift that uses fillers in a unique way to elongate the suspension points between the labiomandibular fold and the mandibular angle, and seems to enhance the mandibular border.
With the modest amount of neck skin laxity and minimal excess fat along the mandibular border shown in the photos, my procedure of choice would be MyEllevate. This is a procedure done with local tumescent anesthesia and should not hurt. Its goal is to draw the neck skin and upper platysma up into the cervicomental angle to get better definition both there and under the jawline, by means of a double-stranded suspension suture.
The suture is place through tiny punctures that do not leave a scar, by means of a light rod to which the suture is attached in the middle. It starts in the midline slightly above the CM angle and is placed subcutaneously up to and behind the ear at the mastoid, then back down and across to the other side and back to the starting point where it is pulled to the appropriate tension and tied. The suture is used at the beginning of the procedure to cut and release the medial border of the platysma to interrupt the platysma bands. Skin tightening is then done if needed, my preference being the Cynosure 1440 directional Sidelaze laser, under the skin, then liposuction as needed, then the MyEllevate suture suspension.
This approach is a second operation, but not as invasive and not as expensive as a face and neck lift.

Morpheus 8 is a non-invasive skin and soft tissue tightening treatment that is consistently amazing in our patients. We use the Morpheus to exact fractional induced RF into the skin or tissue in order to tighten collagen and stimulate contraction of the tissue. For acne scars, it is quite useful to build collagen in patients who have atrophic scars but is not very productive for ice-pick scars which require TCA Cross. For tissue tightening, Morpheus is ideal for the face and neck and we often combine it with CO2 laser or Ultherapy to further enhance results. Chemical peels and skin resurfacing should be done at least 5 to 7 days after, but can be performed earlier, depending on treatment severity. Avoid exfoliating skin treatments before Morpheus and expect a period of 2-4 weeks for skin contraction to set in.

Best,
Dr. Karamanoukian
Realself100 Surgeon

Based on these photos and what you said, my suspicion is that you don't really have much fat left but instead are experiencing some platysma laxity -- as demonstrated by both the jowling and the blunting of the angle in the neck. If that is the case, you need surgery to address the platysma, which neither of the options mentioned would help you with that.

If you are wanting a more defined neck line and jaw you will need to consider something in addition to fillers. You may want to explore FaceTite. This minimally invasive procedure uses RF technology to tighten skin. No general anesthesia is required. I've included a video that I hope you find helpful.