Yes, I think you should ask the doctor. I feel like they are good to go if they have just something treated with antibiotic---- two days into it. But if it is secondary to a virus, then longer is better. Preschools usually say that they want kids to be done with their antibiotics but that is not realistic for 'real' school (kindergarten on). good luck
It depends on what she had. You could ask to talk to her doctor about it.