Okay, I feel like this is the most appropriate place to discuss something that happened to me almost ten years ago.
I went to the hospital for a very, very severe illness, but recovered pretty quickly once I was given the right antibiotics and medication. The problem started a little while later. I hadn't been home long before I started noticing my left bre@st swelling and becoming very tender. Due to a pretty limited (and very inaccurate) knowledge of typical pubescent development, I just assumed I was growing, being around fifteen at the time.
Well, it just got worse and worse to the point that any pressure at all hurt. One day, I came home, and something felt... odd. Took off my bra, and the entire cup was full of thick, bright green pus, not to mention blood. At that point, I did the only thing I could think of and yelled, "Mama!" I had two vertical splits in my nipple, and if I squeezed, more pus would just... pour out.
Turns out, I caught a particularly nasty case of MRSA, and it had turned into mastitis. I had to have surgery to remove everything. I don't know which hurt more, the month before or the weeks after, going in to get the packing changed/removed.