Skinny but still double chin, what to do? I weight 108 pounds at 5'2 (photos)

Hi nika112018,
There are several options for that double chin! I will tell you two recommendations that I would make and you would have to choose based on cost and available downtime...
You may be a candidate for Kybella injections. This is an injection that dissolves the fat under the chin. It is done in the office and you can expect to be swollen for 3-5 days afterwards. Results are usually seen after 2-3 treatments.
For a surgical option that could also help with the loose skin, my recommendation would be SmartLipo of the area. This is a lasertip liposuction technique that first dissolves the fat and tightens the skin and then the fat is suctioned out. This can also be done in the office without a full general anesthetic. Results are seen much quicker...usually by one week after the swelling has gone down. I have my patients wear the "chin strap" for 5 days postop.
First step is finding a good well qualified plastic surgeon that will do a full consultation and exam with you and provide his or her recommendations based on that. Good luck!
Sincerely,
Dr. Howland

Ideally a non smiling side view is needed for better assessment.  it is likely chin lipo or Kybella would be good options to decrease the fat from underneath your chin.  Consult with a few experienced facial plastic surgeons to review your candidacy. 

Thanks for your question. Without multiple views of your chin and problem area it is impossible to say what therapy would be the best for you. For younger patients with good skin elasticity liposuction or kybella may work. A weak jaw can contribute and a chin implant may also be considered. These are all guesses and your best option would be a consultation with an experienced surgeon.
Good luck and I hope this helps,
Dr. Wayne