NWT Selfie Leslie Playa Vista XS/6 (aus) Oster / Ivory Mini Dress

Bought this for my rehearsal dinner and didn’t love the way it fit me and ended up going with a different dress (I’m 5’9 and 125lbs, a small just would have been a better fit) but I never noticed the faint blue markings on the back until now. They might come off - not sure what it is but it is unworn and has just been hanging in my closet with other dresses. Size XS aus size 6 - fit is probably similar to a 0/2.