Hives or a virus?

I feed my 8 month old eggs yesterday morning (her second time having them and she did just fine the first time) I also fed her the baby yogurt in the yogurt section yesterday afternoon. Couple hours later she had explosive diarrhea like down the legs, up the back, through clothes 3 times. Once today. I thought it was teething because she has two more teeth coming in, then I was thinking virus because more kept popping up and it got worse. My mom said it looks like hives but her temp is 100. I posted pictures down below