My 22 year old healthy son had ACL reconstruction surgery 1 week ago and after he visited the Dr. 2 days ago for a follow-up the skin on his knee broke out into a terrible rash about 2 to 3 inches from the incision site. When the Nurse had removed all of the cotton gauze that had been wrapped around his leg, my Son mentioned his leg felt itchy, and we noticed 1 small pustule that was raised and looked fluid filled almost like a blister. We've been administering Benadryl for the past 2 days, but this break-out appears worse. As of yesterday there were several raised blisters along with reddened patchy skin. Now today the blisters have appeared to connect together into 2 large raised blisters that are approximately 3/4 of an inch to 1 inch in size and still appearing fluid filled. The Dr. saw him yesterday and said the reaction was normal and to continue administering the Benadryl. He also wrapped it with a sleeve before putting the brace back on. But we did not receive a reason as to why he's experiencing this, nor what to do if it keeps getting worse. Please any insight you can share would be helpful.