I'm Not Cold, So Why Are My Nipples Hard?Uploader: Grolkis 5 years ago Subscribe 5
This happens because of a surge in estrogen levels. So can certain laundry detergents and fabrics. Inverted nipples typically don't pose a health concern, so treatment isn't necessary. When you stimulate your nipples, your nerves tell your muscles in the area to contract, thus hardening your nipples.