My daughter has dry cracked skin behind her ears. It hurts her when I pull lightly or wash them in the tub. What can be done to help?

Dry skin ears. Try emollient cream (moisturizing) during day & petroleum jelly at night. If that helps but needs more, mix in small dab of Cortaid (hydrocortisone) but use very sparingly. If still not improved, see pediatrician.
Rash behind ears. The most common cause of a rash behind the ears is seborrheic dermatitis (like cradle cap when she was younger). This rash is caused by irritation to the skin from excess oil from her sweat glands. Behind the ears and in the scalp are the most common places. You could start treatment with an over-the-counter cortisone cream, the highest strength you can get. This may do it.