If your little sister has a maculate appearance, she either needs a good wipe with a damp towel or you should take her to the doctor straight away. A fairly technical word little used now, maculate means "spotted" or "blotchy."
There's another meaning for maculate, that of "having a blemished or impure moral character." Now your little sister doesn't have that, does she? You can also maculate something by either physically or metaphorically polluting it — like a river or a relationship.