Speak to a medical professional though, just to be on the safer side. x
I was told that was normal to have a bit of stitch poking out at the end of the scar (due to how the wound is stitched) and that once all the wound has healed on the inside and the stitches dissolved on the inside that the external bit will drop off, and indeed that happened to me. Probably about 4 weeks later.
Mine came out a little bit as well. Had an open wound on top... Docs said that it was ok, as the body heals itself. I left the hanging stitch as it was. Looks like it's disappeared