R.W.
Hey K.!
I'm not sure if your daughter has a cold sore or not, since it's a reaction . . . I used to get cold sores mainly from stress.
About a year ago I started ordering my non-perishable groceries (shampoo, laundry detergent, lotions, soaps, etc)from this really neat online company/store based out of Idaho calld Melaleuca the Wellness Company (www.melaleuca.com).
A lot of their stuff contains tea tree oil (melaleuca oil)
and one of the products "melaleuca oil" I've used on my daughter since she was 6 months for almost everything.
I use it everytime I feel a cold sore coming on (just apply to the area) and haven't got one in a year! yeah!
When Sonora, my 20 month old, get cuts, bug bites, what-have-you, I put the oil on . . .it's like a cure-all, and I don't have to worry about my baby being too young for it since it is all natural.
I'm sorry if that was long, but I think this could help your daughter get rid of the rash once it arrives!
If you have any other questions, you can write me here, or you can email me ____@____.com
R. Wells