Can someone here please tell me what am I going through?

Symptoms: I was cleaning up an old vintage 37 year old keyboard and I was using dawn dish soap, I don't know if it's correlated just mentioning. My legs were becoming purple and my knees were becoming inflamed. Red and hot to the touch, noticeably hotter then the other part of my legs. It was purple net like pattern on my leg, I stopped interacting with it washed my hands and left and it went away after 30 minutes - 60 minutes. It was also slightly itchy but then again I had a mosquito bite there. That's really all. Influences: Dawn Dish Soap?? Dusty crusty old keyboard? (37 year old)?? I never wear shorts so this stuff could have happened before but I was wearing shorts today because I was doing my laundry.

Timeline: I grab the keyboard, I grab a bowl, I pull off keycaps on the gross keyboard and put them inside the bowl, I put some dawn dish soap inside with some water and mix it all around, I look at my legs symptoms show up, I pull it out and let it dry and that's all. (I never use dawn dish soap this has happened twice while I was cleaning the the keyboards other caps it has two for some reason this is my second time using dawn dish soap)

I'm not bothered to type it all again but can someone please explain my symptoms?