Unfortunately, I don't believe there really isn't much you can do but let it run its course. I would close tomorrow and then see how the other kids are in your care to see if you need to be closed until further notice.
I personally have not had it go through my daycare, but my daughter did have it last year, and it took a few days for it to run its course and her feel better.
Did you have to close inorder to aatend to the needs of your DD?