Marc Jacobs dress

Marc by Marc Jacobs dress. Full, twirly skirt, fitted top with ruffle around scoop neckline and exposed zipper in back. No size tag but I would say it fits like a medium (I’m a size small and I can wear it but it’s a little loose; it also has some stretch). Some discoloration under arms (see photos); I have not tried to get it out. Not really noticeable when worn.