Which procedure would help me achieve a tightened lower face and defined jaw line? 24 y/o (photos)

From your photos and descriptions of your concerns you seems to be a candidate for Morpheus8. This treatment combines RF technology with microneedling to improve overall skin tone and texture. Three sessions are recommended for optimal results. You can learn more by visiting my website or a provider near you.l

For a more sculpted appearance, I would recommend liposuction with Renuvion skin tightening to the jawline. This would provide a nice result with minimal scarring.

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

Don't be so quick to dismiss the use of facial fillers. HA fillers, in particular, are natural and can be easily dissolved should the need ever arise and a proven track record for safety and efficacy for facial contouring of cheeks, jawlines, etc. Unlike surgery, they yield immediate results and engender little to no significant posttreatment downtime. Surgery, on the other hand, tends to be expensive and typically is followed by significant posttreatment downtime. And, despite the promises of permanent results, most surgeries require follow-up surgical procedures only a few years down the line. What's more, they pull tissue tighter, rather than resupplying volume, which is the primary reason for skin sagging. No doubt you will also be offered fraxel lasers, RF gizmo treatments. A hefty dose of buyer beware is recommended when considering treatment with these expensive "here-today-gone-tomorrow," fancy-named bells and whistles. However, the hard science to support their use lags well behind the heavy marketing and social media buzz to promote them. You would be wise to make sure to consult an experienced, board certified cosmetic dermatologist filler expert to explore this further. Hope this helps and my best for the holidays.

Based on your photos, you could be an excellent candidate for an elastic lift. (See link)
Best of luck !