Hands became swollen, red/purple, have water blisters, and painful

The first day my hands were itchy but no signs of redness. The 2nd day my hands became swollen and red with pains like a sunburn. The 3rd day my hands became more red with some purple. Water blisters are forming and the pain and swelling are worse. I can tell more water blisters will be forming. What medication should I take to decrease my symptoms? My dermatologist saw my hands when they were just swollen and red. She suggested Zyrtec because she thought it was an allergy reaction. I have been taking benadryl instead because that was what I had at my house. I included a picture of how my hands currently look like. I also have been applying a thin layer of cortisone because a pharmacist believed that my hands had a severe burn. My hands are very painful and warm at the moment. Please help!