What Causes Blackheads On Armpit Oozing Smelly Discharge When Squeezed?

I have what look like two blackheads in my armpit. I squeezed it and had flesh colored discharge that smells. It was bigger before. I think I got rid of a skin tag in that armpit a few months before. Should I see a doctor right away. Can this be cancer. I am a female and it's hard for me to do breast exam because I have always had lumpy breasts. A doctor told me a long time ago I have naturally lumpy breasts.