What is the pulling sensation and tightness under my chin after liposuction?

A tight feeling can occur after neck liposuction for several reasons, including fibrosis in this area and skin adherence to the underlying platysma muscle.  Massage can be helpful.  In rare cases, further corrective measures can be taken including surgical submentoplasty, therapuetic ultrasound, or injections. 

It is uncommon to have new onset problems develop 6 months following a surgical procedure. It is not likely to be an infection, but I would recommend a follow-up with your surgeon. Good luck