What do you do when your ten month old nipple piercing starts bleeding?

It can take up to a year and a half for nipple piercings to be totally healed, so don't freak out about this. Wash them like you would when you first got them done, and be very gentle. My other suggestion is a warm salt water soak with about 1/4 teaspoon of non-iodized salt and 8 oz warm water. This should ease any pressure, and clean up any small infection that might be there.