I want to know the recommended number of sessions for a double chin lift to lift sagging skin.

Perhaps due to my habit of looking at my smartphone frequently, my jawline started to sag and the skin under my chin began to fold at some point. Since I get a double chin even when I lower my head just a little, I get so upset every time I take a photo. So, I have decided to bite the bullet and get proper double chin lifting treatment. I see there are many types, such as injections and ultrasound, and I am curious how many sessions are typically required to see a noticeable slimming effect. I know it varies by clinic, but I would like to know what the general schedule for double chin lifting is. I am waiting for realistic advice from those with experience on whether a single session is effective or if I need at least three sessions to get the line right.