Size Small Gap Dress

Super cute pink and white zigzag sleeveless dress in good pre-owned condition by GAP. It has attached gathered tie and pockets. I just noticed a stain while I was steaming it.I don't know what it is, I have never worn it. Size small. Fully lined. Measures 17" armpit to armpit, 36" shoulder to hem. Shell 100% rayon Lining-100% polyester Machine wash cold gentle, line dry, warm iron.