Young thin people who have a double chin almost always do so because of an imbalance between their mandible (jaw bone) and maxilla(mid face).
This appears to be the case with you.
Even when that's the case if you have a substantial amount of fat then liposuction will give an impressive result...
Your surgeon would have advised you on the MLD massage. However, everyone has their own postop protocol. Contact your surgeon to advise you.
Induration does occur post VASER. The massage is to minimise this and stimulate lymphatic flow.
Fibrotic tissue can be softened too.
Eventually...
This is most likely a postural natural skin fold. When you sit down this is where your skin folds naturally. Now that there is a healing process this may become permanent if you do not wear a foam support that prevents the skin from folding.
Having MLD massage can also help. ...