What question is left to ask? there is some fibres that does not originate in your biochemistry stuck in yout hair, and there are some materials that originate in you stuck in that bunde of fibres that was previously resting on your cranium.

Why is it important to have a sharp definition of "self," is it not to presume it has intristic meaning? What you refer to as "you" is an emergent system that has causes in your entire past light cone and repercussions in your entire future lightcone. There is a constant flux of matter and energy sorrounding the substrate that runs your consciousnness program. It is a continuous construct, there isn't a line to be drawn at all.