I don't see why you need to "confront" your babysitter. You certainly need to ask about the rash and that you didn't see the need for the dirty area around his nose and face. Ask what she uses to wipe his face, if she is using diaper wipes, they are likely too harsh. Ask that she use wash clothes, even provide them for your son, also ask if she uses soap when wiping it off, perhaps what she uses is too harsh, perhaps plain warm water after a snack and meals would be enough, soap only when necessary. baby power really isn't necessary and harmful for lungs, but really not a big deal that it got spilled, how do you know it was the other kids? it sounds like it is time for you to schedule a time where you chat about things and see if you feel comfortable in keeping her as your babysitter. Communication is so important, it is my one big issue as a home child care provider, you need to express, nicely of course, any issues or problems that you see. It is the way for things to be resolved, and if it doeesn't change, then switch, but you likely won't find the perfect babysitter, keep in mind, you may switch one issue for something else.