If you're worried about sagging jawline, I really highly recommend InMode FX.

I gained some weight last winter, and my double chin got really bad. It reached the point where my chin would fold even without bending my head down, so I was totally shocked and signed up for 3 sessions of InMode FX. The results were seriously amazing! It was hot during the treatment so I teared up a little, and I had a bruise under my chin that lasted about a week, but after a month, the V-line that had been hidden in my jawline suddenly appeared! I plan to go back soon for another session to maintain the results for the summer.