What Causes Red Bump On Areola?

I have a red...bump? On my right areola. It almost looks like a pimple. It s extremely sensitive. It reminds me of when I was breast feeding & LO would skip a feeding, and sometimes it s throbbing. I m curious what it could be from. I see the GYNO on Tuesday but wasn t sure if it was something that should be checked out sooner. Thank you!