Could The Recurrence Of Bumps Under The Armpits Be Due To Cancer?

Age: 24 Weight: 215 Height: 5'5" Medical History: cancer runs in the family. - My query: Ever since I gave birth, I get these tiny bumps in my armpits but I assumed they were acne because I have a huge skin problem & some of them squirted puss out, were red & went away or acted just like acne. But now I have a 1/2 dime size bump that actually has three pen-tip size holes in them. Does this sound like something that needs immediate attention? Because I don't have insurance & if it's something I don't need to worry about, then I won't. But I know merca (unsure of spelling?) is big this year & could it possibly be that because of the holes in it? I've seen others who have had it & I don't want to touch my son if that is the possibility. I know, I should go see a physician, but again, no insurance so I want to make sure it's something that sounds like it needs immediate attention. Thank you.