She found Marie under her bed, way underneath in a corner. Marie was under her bed from the very first day she got to Hogwarts. I didn't know her before she came to Hogwarts but Draco did and he says she was different before. And she changed after the start of the year, she was different when I first met her.

I think it's Marie, and just like it took time for Marie to really start changing Pansy it's taking time for her its changes to wear off.