Is it just me or does the woman portraying "Mandy" throughout the entire length of the sexual gathering at the mansion, have a body that doesn't AT ALL resemble the original "Mandy" we met in the opening of the film?

The woman who overdosed had very defined, muscular arms and shoulders and her breasts were plump and oval shaped. The "Mandy" at the mansion had very slender, lean arms, slacker shoulders and much pointier "natural" breasts. (01:22:40 in)