I Had A Small Bite Or Pimple In The Center

i had a small bite or pimple in the center of my back on thursday of last week then by friday the bump had popped and friday evening by the time i looked at it friday evening it formed a large red space about the size of a womans fist in the center of my back i used benadril topical cream on it as well as an antibiotic ointment on it now it feels like leather on my skin i also noticed similar spots under each side of by breast
what can i use