Speaking from the perspective of someone who is married to a doctor, and the daughter of a nurse, I find it plausible that she could have simply asked her sister for advice on the best way to keep the cuts clean-- particularly if she had been told to clean them at some particular interval.
I do this all the time with my husband and my mom when I have a question about how to best care for some ailment my son or myself might have. Again, this is all just my opinion, but it seems plausible to me.
If the stitches were done on a Monday and the teenager was back in Missouri on a Wednesday, would RZ have had to do anything to them?