"Do" is actually a noun here, meaning (hair) style. A hairdo is a hair style in general, and an "up do" is a style where the hair is piled on top of the head. A "pouffy do" suggests a fluffy voluminous style with lots of backcombing and lacquer.

Hi. Aah yes, I see why you're confused. In this case, 'do' is short for 'hairdo' (hairstyle). So to say she had a 'pouffy do' means that her hair was styled in a way that had a lot of air in it (perhaps like a 'beehive' hairstyle) or was very volumised- but this word has a sort of negative feel.

My guess is "do" comes from "hair-do" which is another way of saying hair style. Pouffy do would be a hair style that is really fluffy and airy piled onto someone's head.