Nipple pimple?!

Samantha • Life is short. Find someone to love completely.
Ok. This has never happened to me before.
My nipple has been sore the last couple of days. I thought it might have something to do with my new bra.
BUT I took a closer look today.
My nipple looked like maybe there could be a pimple under there. (SORRY, that's kinda gross...)
So, I just decided I would try to get something out.
White came out. Kinda like a pimple.
HAS THIS HAPPENED TO ANYONE ELSE?!
Could it have something to do with breastfeeding? (I don't breastfeed anymore. I stopped about 2 months ago.)