My oldest has never been a milk drinker; she's a meat and potatoes eater without much of a sweet tooth. I assumed she didn't process dairy well since she didn't like it, but we had an accidental confirmation when she cut out grains as an experiment (don't remember why) and went on a green tea latte kick. She was eating yogurt and cheese to fill up without the grains, and with the daily large homemade latte, her dairy consumption went from probably 1 serving a day to 4 or 5. Within a week, she came to me with a fine rash on her cheeks and asked what was wrong and if she was about to break out. I assured her it was most likely milk rash and she should scale back to where she was before. It went away in a few days. Dairy, along with sugar, is a trigger of skin problems for many people. If your daughter is having challenges with her skin, and she's open to ideas, you could look for ways to cut back or eliminate it, and see if it makes a difference. Many people find that some types of dairy are fine, while others are not, and from talking with many clients it seems that milk and common cheeses are the first things that should go. Kids often lose their taste for milk as they get older, and this is likely related to the decrease in milk-digesting enzymes.
Have any of your children lost interest in milk or never cared for it? Have any of them cut out dairy to help their skin?