Hi My Husband Went To His GP On Thursday And

Hi my husband went to his GP on Thursday and was sent to a Dermotologis on Friday.
He started with a small bump which appeared as an ant bite or infected hair (is what My husband was thinking) earlier in the week, he was going to work Tuesday night and took a hard chill. He is never cold, wears shorts when it is literally in the teens. The next day he saw a few more spits had appeared and was causing him pain on the chin but by Wednesday night when he had his leg elevated I was stunned to see that it was red plus more spots had appeared and warm to touch. The first spot that appeared had puss in it and I thought maybe the shingles or phlebitis. The GP took some blood samples and gave him antibiotic and the Dermatologist gave him a topical cortisone cream for inflammation. It is paining him so much to walk or just let his leg down plus it is still very red, I am very concerned his is type 2 diabetic and is in afib.
What should we do or what do you think this is?