About A Month Ago, We Had A Church Function, The

about a month ago, we had a church function, the food was catered with aluminum pans with tops. I opened the top and received a small scratch on my finger. within days, I noticed that the scratch turned into a open sore that would leak a clear fluid with a blister. I cleaned it with peroxide and water, and it got worse. Not only is it on my index finger, but has spread to other fingers on the other hand as well. I now have 3 fingers and my left thumb leaking fluid and blisters. What could it be?