Banana Bread Gone Terribly Wrong

My poor little Guy. He loves to cook with me so I decided to make a Banana Bread Mix with him this afternoon. (Every morning, he stirs up his Cheerios and says, "Mama, I cook". He did great and there was little to no mess. He poured the measuring cups in the large bowl, just as I had instructed him to. After I put it in the oven, I washed his hands and cleaned off the table. So how he got SOMETHING in his eye and on his face, I just don't know. At first, he was rubbing his eyes and I thought he was still sleepy, as he just woke up from a long nap. Then, I turned around to see his face look like THIS. I immediately knew he was having some sort of allergic reaction but couldn't figure out what it was. If it was the mix, would THAT make his face so splotchy? He didn't complain a bit but he put his cup of cold milk to his face so I knew it was burning him. He also asked for his frog we keep in the freezer. He loves it when he has a boo boo and even when he doesn't. Mike took him upstairs and washed his face with a cool cloth and then went to Walgreen's to get him some medicine. The Pharmacist was really helpful and said that the Children's Benadryl would knock it right out. His right eye was still swollen shut when he went to bed but the puffiness and redness had gone down a lot. He was in good spirits and never complained, though. I felt HORRIBLE. I know we cleaned up but I guess these things happen. I just hated to see him hurt. Hoping all will be better in the morning...My precious little boy.