I developed a poison ivy rash about 3 weeks ago. Since then my arm has swollen and I did go to the doctor and they put me on steriods and antibiotics. Now, although the blisters are gone, the area is still red, itchy and a strange circle has developed about an inch out from the original infection. Round patch, white strip, red strip kind of a thing. Do I need to go back to the doctor or is this just the way an infection like this progresses?