What Does A Lump On Breast Indicate?

Hello....I am a 20 yr old girl. from Few weeks i have been noticing a small lump in my right breast. one day during bathing i squeezed it hard and a little pus like liquid came out and after that a little blood. i saw tiny black few granule like substance beneath its skin... Can u suggest what it is and what i should do now. there is no other symptoms on the skin.Is that any kind of cancer..??