What Would Cause Pus Filled Bump On Stomach?

i have a bump on my stomach...it has been there for a week. it is about half way between my breast and naval. at first it looked like an ant bite, itched and stung like an ant bite...so i squeezed it. it has gotten worse every day and hurts even when i am not doing anything. it is red, with a a small pus center and now has a little black dot in the center. very painful to touch it and very swollen under the skin. i think it is getting better, but now i have a new 'ant bite looking bump' on the opposite side of my stomach. this one is right above my panty line. any ideas as to what it could be?