Why does my nipple taste bitter?

My boyfriend sucked / licked my nipple and right after he pulled back and made a face. He said when he licks around the nipple it tastes bitter. I have no idea why that would be, I just got out of the shower so it’s not like I’m actually dirty. I shower daily. And also, I was recently pregnant and had a miscarriage. I still haven’t had a period after my miscarriage so it’s pretty recent. Does that have anything to do with or what is going on.