2 month old with servere rash

I have a 2 month old baby girl.  She has been seen by her pediatritian for a rash that is mainly on her sides and tops of her shoulders. The rash first appeared about 2 weeks ago. We haven't made any changes to any products such as lotions, body washes, or laundry detergents on her or myself. The dr tells me there isn't much we can do at this age but the rash continues to get worse. I have now stopped using anything on her skin because i don't know what is going to irratate it. I read about and seen pictures of ecxema on infants and this doesn't look much like the pictures I have seen. In description it is more like what I have read about baby acne. The bumps are on a red base and have yellowish kind of dry looking raised centers. From what I have read though this is not the common place for infant acne, that alot of the time when the rash is only in these places it is likely that the child is having a reaction to laundry soap or the clothing itself. As I said before none of these things have changed since birth , so it is hard for me to go with that logic. I have also though to myself anytime she gets hot it looks worse but I have read that this is true with most rashes and not just prickly heat, which from the pictures I have seen it doesn't seem to resemble either. I guess my feeling is that this is baby acne. I really need to know if where the rash is would go along with that theory. Again nothing has changed before the rash appeared, she has always been bathed about 3 times a week with johnson's baby wash and warm water, only johnson's lotion. Wet clothes have always been changed almost immediatly. I have now stopped using any soap eccept for uner her neck and her hair and no lotion. We were also using All for Babies on her laundry now I have switched to arm and hammer, which a friend recommended as her son had skin problems when he was a baby and that is what her dermatologist reccomended, and the changing of laundry soap hasn't seemed to make it better or get worse at a more rapid rate than it already was progressing. I need some advice. I already have her scheduled to see a dermatologist but of course it isn't for another 2 weeks. What can I do in the mean time. Thanks in advance.