If you say to her it is time to go (rather than does she need to go?) will she go then? Or does she really resist it? I agree with what the others have said in that I would be taking her at scheduled intervals and have her back in night nappies until at least the rash clears up. Then I would still use night nappies until she is better during the day. I wouldn't make a big fuss but would be pretty firm that when I said it was time, then it is time.