How do you know if the wisdom teeth stiches came out? what does it feel like?

See dentist: You will probably need to see your dentist to confirm that they are gone. Some stitches do dissolve on their own. If these are the type you had placed you shouldn't worry. If you are unsure see your dentist.

Contact oral surgeon: If you are concerned, contact the oral surgeon. The dentist may have placed gut sutures, which dissolve over time.

Depends: depends, most suture are dissolvable and only built to last 24-48hrs (max 5-7days) so you may not feel anything. No if it was silk then you would either still have the string in there or you swallowed it (no worries and it will pass). So if you are managing the pain and you are keeping it clean I would not worry but if you still have questions/issues just call the DR that did the extractions.