I have double chin and I hate it. I'm 35 years old and I'm very thin. I visited several doctors. Any suggestion? (photo)

Thanks for the pictures but a better pictures with your chin parallel with the ground would give a better sense of your issues.  If loose skin is your issue then this is best addressed with necklift/facelift.  If you have only excess fat then liposuction or laser liposuction (laser destroys the fat) would be beneficial.

In the photograph you are actively flexing your neck which can create contour irregularities unrelated to aging or surplus fat in the chin and neck. Post a photograph with the neck in neutral particularly the lateral view.

Hi. First, your photos are taken from below and you are forcing your neck down whihc does not accurately reflect what your neck would look like under normal circumstances. This position and views accentuate the double chin look. IMHO you ae young enough to have lipo of the neck/chin and have very nice result. Good luck, Dr. PG