How can i choose a good surgeon for my chin liposuction? are there any credentials i should look for in a doctor doing chin liposuction?

Credentials-wise : Credentials-wise you mainly want to make sure that your surgeon is board certified in facial plastic surgery or plastic surgery. Another important thing is that you like the results that you see in the before and after photos they show you.

Find : Find an experienced surgeon in your community who shows you multiple examples of good results. If you have good skin tone, you should expect a satisfactory post-op appearance.

Board certification: Make sure your surgeon is board certified in plastic surgery. Be wary of false advertisement of "cosmetic surgeons". There is nothing such as " board of cosmetic surgery".

Many Resources.: I would suggest starting with the american society of plastic surgery and/or the aesthetic society of plastic surgery to obtain a list of well experienced board-certified plastic surgeons.
 then, i would suggest you visit a few surgeons whose practices  concentrate him on aesthetic surgery. Ask  to see lots of examples of their work and preferably speak/see patients who have had similar procedures.