Can I hide my chin implant scar with a hair transplant?

You can use body hair to do a beard or mustache hair transplant . You have to make sure they are the Sam texture and caliber hair. It is a very meticulous and involved procedure, but If it is done by an experienced hair restoration specielaist the outcome is very natural. 

Beard hair transpalnt is very possible and depending on the size of the area, easily done with FUE grafts.  Many hair transplant surgeons like myself will specialize in this type of surgery (although some doctors prefer NOT to do this surgery) so check out who has a special interest and experience.  Good luck!