My Boyfriend Has Had A Skin Condition On His Left

My boyfriend has had a skin condition on his left forearm for 3-4 weeks. A tiny whitehead forms on his forearm and within a couple of day has sprouted a 2-1/2" diameter oozing sore with a 1/4" size hole in the center. It is like a small mountain--worse than a boil. The surrounding skin is very red and tender. He has been on two types of antibiotics and they have been completely ineffective. In fact, the sores keep spreading. He now has 3-4 new sores on his arm. All oozing and horrible. He keeps using antibiotic soap and bandaging them. But they are horrific looking. At times, his entire arm aches and hurts.