This morning my DD woke up with a spotty rash on her back and chest/stomach. First I thought it might be a heat rash or sweat rash but she hasnt had a shirt on all day and it's still there? She's quite grumpy too, bit out of sorts. I just checked her temp and it was only 35.5, so no fever.
Does anyone have any suggestions what it could be?

Thankyou

I forgot to add that she had a 3 hour morning sleep today and woke up at 1pm and shes down for another sleep already. VERY strange for her to sleep that much.