After Sally emerges from the water while she's exploring, for an instant her hair seems swept back and pressed down, clearly drenched. During the next shot, which is a close-up, her hair looks as if it had been hastily dried with a towel, even though we never even see her touch her hair.
During the shots of the youngest girl (Sarah) underwater, she is shown with the markings on her face that she puts in place later in the movie as war paint.