Hello JACustomer/ Neil,
Thank you so much for attaching those images, it is true that a picture indeed says a thousand words. That does look to be incredibly painful, and I hope I can be of some help here. Please understand though that online (or offline for that matter) I can not diagnose or state with certainty what anything is, I can only give my best educated guess based on what I see.
Dermatology can be quite a challenge, and it is one reason why health care is as much art as it is science; two practitioners can look at a rash, and much like looking at a painting, come to two different interpretations of what they see. I can certainly understand looking at that why your treating doctor believed it may be erythema multiforme, but there is no history of any new medications or anything that she could be having such a bad allergic type of reaction to. The worst case scenario of this type of reaction is called "XXXXX XXXXX syndrome" (I am NOT saying she has this, not by a long shot...this is for information only; the worst possible outcome) and people can be hospitalized with it and it can indeed be life threatening. Here is more information on this: http://www.mayoclinic.com/health/stevens-johnson-syndrome/DS00940
So I am not and can not discount the possibility that there is some degree of erythema multiforme happening here, and she should be treated for this (as is appropriate) if this is a thought. Yet, when I look at these images, I wonder if I am looking at a bacterial rash called impetigo.
Impetigo is caused by either staph or strep bacteria and can be quite contagious. In children, its generally acquired originally through a cut of some type and spreads as the child scratches or rubs at the sores. There are several different types of impetigo but its hallmark features are the red blister like sores that rupture and form a yellowish crust, which is not only like what you describe, but I think I see some of that yellow crusting in the middle picture on the left side of the lesion. Impetigo is cured with the appropriate antibiotics; it can be treated easily, but untreated it can have some bad complications relating to the infection. More information on Impetigo is available here: http://www.mayoclinic.com/health/impetigo/DS00464
Images of Impetigo are here: http://www.dermnet.com/images/Impetigo
Your daughter has had these for a while, and they seem not to be improving. I think a good suggestion here is a consult with a dermatologist, as they specialize in skin disease and skin disorders. That way, she can get appropriate diagnosis and correct treatment.
I hope I was able to help, and that she feels better soon.
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