I'm not sure what this is? It started off with one big white head that was painful and I put some salicylic  acid spot treatment at night and woke up and it was crusty yellow crusty and painful.  My doctor said it's impetigo and prescribed me bactroban ointment. However I think it could be a cold sore? My nurse friend said it doesn't look like cold sore and looks more like a pimple with staph. I would some other perspectives