On the nipples is mostly on pregnant women, but they are extremely common on both genders.

They are quite common on the eyelids, especially in teens and young adults of either gender. These are best left to an eye doctor since they are so close to the eye.

They are just oil glands where the skin grows over the opening.

Do not go by what I say, BUT... I think you could pop them like zits - or otherwise drain the oil from them and they would subside.

I would see a dermatologist about them.