A weird pimple where?

Hi friends, I need some advice! I was showering when I noticed a white pearly bump on my nipple. It doesn’t itch, hurt or ooze anything. My mom says it could just be an acne spot, and I’m somewhat positive that’s what it is. It’s been a month since my boyfriend and I have had unprotected sex, I’m on birth control pills and take them around the same time everyday for four years, and nothing has been off or weird with my body. No missed periods or late periods. So this is why I’m thinking that it could be acne. Any advice or tips? Thank you!