How long it takes for the turkey chin effect to disappear after Kybellas first session?

Kybella takes roughly 4-6 weeks to see the full result but in the clinical trials most patients required 4-6 treatments to achieve a satisfactory result. 
Many physicians sell kybella in a 2-3 treatment pack realizing that it takes more that one treatment for most individuals. 
If your 6-8 weeks after your first treatment and still hoping for more improvement I would see a board certified plastic surgeon and discuss a second treatment or submental liposuction. 

"​It takes a series of treatments to get good results with Kybella. Keep in mind, Kybella is good for dissolving the submental fat under the chin area while contouring the jawline and making the chin more defined, but a combination approach is needed to get the most improvement with non-invasive options. I recommend a combination approach with Thermage, Ultherapy, and Exilis.

InMode FaceTite / AccuTite with VASER Neck Liposuction is the best option for contouring and tightening the chin, neck, and jawline area. I recommend getting a formal evaluation with a cosmetic dermatologist. Best, Dr. Emer​​"

Hello and thank you for your question.  Kybella results are noticeable at four to six weeks.  Multiple treatments are typically necessary and the results are gradual. After the 6 weeks, you could certainly receive your second treatment if you desire.  I would recommend a consult with a board certified provider who can discuss with you the options and your desired outcome.  I hope this information helps and best of luck!