I have a few small moles (one on my nipple?!) that have black concave dots in them (like holes). one even falls off and comes back?! cause for concern

Blackheads: These sound like blackheads around your nipple, which is not uncommon. These occur due to plugging of oil/sebaceous ducts in the skin, are are not related to the development of breast cancer.

No: Molluscum have no hairs & once they drop off they do not grow back. The picture is a benign intradermal nevus. Those which fall off may be seborrheic keratoses or acrochordons: all benign. Easy to remove these if they annoy you. No suturing needed.