Rash on my 5 week old

Does anyone know what this could be? Its very dry, bumpy and red. It doesnt seem to bother my daughter and shes acting completely normal but it has been coming and going for over a week now. All her sheets have been washed and all her clothes and my clothes in the same wash soap (shes had no reaction on her body just her face and neck) i really thought her sheets were the problem as its on the sode of her face she lies most, but after washing them she woke up this morning on her other side with a small rash starting there too. I dont know what to do, my doctors first available appointment isnt until tomorrow afternoon