This is in all possibilities a boil which has been aggravated following manipulation from your end. Since the axilla
comprises of loose tissue, the collection of pus might continue to increase without it being more apparent on the surface. It is best to visit a surgeon at this point of time because you would possibly need an incision and drainage
to relieve yourself from the symptoms along with the intake of antibiotics. Do not delay because the pain would continue to increase in the absence of treatment!