Hello, I Have A Collection Of Black Fluid In My

hello,

i have a collection of black fluid in my axilla noticed yesterday was very tender and warm, now has cooled off after rest and applying bandage over it. it is tense does not burst, at the base can feel something hard, no surrounding redness. I was up all night yesterday, may be related to using computer too much as I realize when I am on the computer that area is compressed.