There are multiple ways of starting a subcuticular suture. In this case you will have tails sticking out of each side and you will trim them in the clinic after the wound has healed. You’d think that without a knot the suture could slip out and the wound cut split open, but the friction between the suture and the dermis tends to be enough to keep that from happening. Regardless, this is typically reinforced with skin glue or steri strips, which is a tape placed over the incision to help keep it