Split stitches/sutures in mouth from chin implant procedure. Will the area heal by itself or should I get it re-stitched?

It is difficult to answer your question without examining you.  Since the wound in your mouth from your chin implant has re-opened, you should be evaluated in person to determine the appropriate treatment.  I would try and see a plastic surgeon or facial plastic surgeon who is experienced with chin implants.  

Once tissues have been operated on and become inflamed, they will not hold sutures well. As long as the implant is not exposed, it may well heal on its own. But that will depend on how far below the implant is from the incision and what type of material the implant is composed of.

Ordinarily, when we suture in the mouth we use stitches that are meant to dissolve. Usually two weeks is plenty of time to allow proper healing. The decision to have additional repair work simply depends on how well you are healing. Usually mouths heal pretty quickly. However, the placement of the implant increases your chance of having trouble. The last thing you'd want is an infected implant. It's time to be evaluated by a surgeon who does chin implants. They can determine if you're healing well, if you're infected, or if you need any additional repair work.Good luck!