When my youngest daughter was three, her complexion was slightly mottled on the cheeks and at the throat. It was like this for some months and I didn’t really think anything of it; I thought it was just the way she was. But then one night, as an experiment, I gave her cheeks a good scrub with a face washer and the mottling came off. She was just dirty! My partner is the one to bathe our children half the time, and my mother has the children for a sleepover most weekends, so all three of us hung our heads in shame.