Would Kybella help tighten/define my jawline? (photos)

Dear TZ5256,Kybella typically takes 3 to 5 treatments to work. This is why I've stopped carrying Kybella in my office.  I recommend neck liposuction more often then any injectable procedure for the neck now. It provides superior results gives me more control over the area than any injectable.  It also costs about the same as what you paid for your first kybella session. The liposuction can be done under local while awake in the office and recovery is about the same as kybella.Daniel Barrett, MD
Certified, American Board of Plastic Surgery
Member, American Society of Plastic Surgery
Member, American Society of Aesthetic Plastic Surgery

Kybella is an FDA approved non-invasive treatment for reducing chin and neck fat. Unlike surgery, Kybella has very little downtime and no anesthesia is required. For best results, there are four to six rounds of Kybella injections over a six month period. It takes a series of treatments to get good results with Kybella. Keep in mind, Kybella is good for dissolving fat under the chin, but a combination approach is needed to get the most improvement with non-invasive options. I recommend a combination approach with Thermage, Ultherapy, Exilis. VASER Liposuction in combination with ThermiRF is the best alternative for contouring the chin. I recommend getting a formal evaluation with a cosmetic dermatologist. Best, Dr. Emer

Both Kybella or neck liposuction are good options and will improve the double chin. It depends on your lifestyle and personality which would be better for you. 
Kybella is best for patients that:
1)  Do not want surgery 
2)  Are not surgical candidates 
3)  Not willing to wear a compression dressing around the face for 1 week 
4)  Patient-  The results of Kybella will take months
Kybella take 1-3 treatments every 6 weeks.  Patient will develop swelling and possible bruising after each injection that may last a few days.  The benefit of Kybella is each treatment is quick and completed in the office. However, some patients need more than one treatment to get desired results. 
Neck Liposuction is best for patients that:
1)  Want a single treatment 
2)  One recovery time-  Downtime for neck liposuction require wearing a wrap around face for 1 week. 3)  Less painful 
4)  Quicker results 
5)  Cost is a concern
Neck liposuction is a quick surgical procedure that can be complete while the patient is awake.  It cost around the same price a Kybella and can be less in patients with heavier necks.  The single recovery of neck liposuction may be a better option for some patients.
I hope this helps.