I accidentally applied neosporin instead of diaper rash cream on daughter's vagina will this hurt her?

Doubtful. Some kids can have an intolerance or allergic reaction to anything you put on their skin, especially in sensitive areas.Luckily that is rare in infants and to that medication.In the future if you want to do a trial for skin sensitivity, you can put a small amt on the pad of a bandaid, apply it to a clear skin site like the back & check it over the next day.No break out,no sensitivity.