I had a black spot on my breast, it was itchy so i scratched it then it became like a pimple. i squeezed it then white pus came out then black pus?

Blackhead: It sounds like you had a clogged pore or blackhead. When you scratched it, the bacteria normally on your skin were able to make their way underneath and cause a mild infection. This was the white pus that you noted. If it does not resolve completely, you should see your doctor. A picture is always helpful when trying to diagnose a skin problem.