Blood came out of my nipple when my partner sucked it but did not bite it during sex. Do I need to have that checked? I'm not pregnant.

Probably. The recommendation for most women without a family history of breast cancer is to have a baseline mammogram between ages 35-40. Bleeding from the nipple may be a warning sign for underlying breast disease up to and including cancer of the breast. You may need a diagnostic mammogram given any breast symptoms such as bleeding, pain, palpable mass or any nipple discharge.