Looking for a little help here...

DS had little sore on his leg, which he picked at, so we put a bandaid on it overnight It was a plastic one cause that was all I had in the house). Took the bandaid off the next day to let it air, and not only had the sore gotten worse and looked infected, but he had all these little blisters / sores where the adhesive was. No more bandaids have been used, and I cleaned it with dettol, and put some antibiotic cream on it, but things are not looking any better, and there seem to be more blisters coming up, and still lots of redness.

Is there anything I can do, or should I be heading to a Dr. I feel so bad...