Lilly has just undergone heartworm treatment lately and is now on antibiotics for a raised white blood cell count of unknown origen. These past few days she has developed a large area of inchy rash under her front armpit. She scratches it frequently . It does not smell and the red dots are not raised or oozing. She is on Revolution and I have seen no fleas. Anyone know how I should treat this. She is taking probiotics while she is on antibiotics.