Anyone know what this is? We are going to head to the ER soon. I noticed it when we woke up this…

Anyone know what this is? We are going to head to the ER soon. I noticed it when we woke up this morning and initially chalked it up to pressure marks from how she slept. But then as the day went on it seemed to spread in some places and go away I'm other. Like I would see it on her foot then a few minutes later it would be home but it now covers her back pretty much with splotches everywhere else. It's not on her hands or the bottom of her feet. Started on her chest but has been everywhere. Face legs arms and back. I thought it looked like an allergy rash and I still think that's what it looks like but because of how it spread I'm going to go ahead and take her to the ER. I'm not sure if it's even related but she has a cold too.