WHAT IS THIS?!

Maddie ♊️ • Howdy partners

I had something like this in the exact same spot a while ago, accept it was much less aggravated. It then scabbed over and essentially went away. I wake up this morning to this... WTF?! It lies just below the bottom of my underwire, so I don’t think its irritation. It also feels full, the way an under the skin pimple feels. What is it and how do I get

rid of it? It also is much more red in person, less pink than in the picture.