We find these tiny fragments, and they tell us something about the past, but every artefact invites a lot more questions than it provides answers.
My late father spent some time researching tattoos and body marks in antiquity. A common pattern that appeared often were 4 dots arranged like the vertices of a rhombus. The pattern appears eg. on terracotta figurines and must have had some significance. But we have no idea what it meant, and all we can do is make wild guesses.