What could this be?

My daughter is 1 and she broke out to some laundry detergent that I got clothes off of someone, she was about 3 months old. Well now she starting to cut her back teeth so she been running a fever well I kept a eye on her temperature and then she wanted to play outside so I took her sleeper off and noticed she was broke out some on her belly and i looked on her back and she was broke out more, well I was looking when she fell asleep it was on her face.