Suggest Treatment For Bloody Lump In Armpit

I have had a lump under my armpit.. it looks like a big cyst. I ve had it for like a month now. I ve tried squeezing it to see if anything comes out. Nothing would. Well, I was in the bathroom taking a shower and decided to try to pop it like a pimple after leaving it alone for a week. Well when I did blood squirted out. Then like a clearish red come out of it. Only on one side of it. The other side was almost black. My boyfriend says it s cuz it s filled with blood. He told me to leave it alone after I got everything I could out of it. And it should be ready to pop again tommorow. Well I was laying in bed and just touched it.... i noticed there was blood on my fingers, and got up to wash my hands. Then come back into the bedroom and it squirted all over my pillow!! What is this? Is it going to go away?