Dylan Lauren rocked a unique accessory at her father Ralph’s Fashion Week show yesterday — an arm cast. The Dylan’s Candy Bar impresario explained: “I was wearing these anti-slip grips you wear on the ice . . . and I slipped on marble instead.” But being a Lauren, she still found a way to make her bandages chic. “I have more colors . . . I change it up. [For] Valentine’s Day, it looks like candy canes.” Lauren, who’s stuck with the cast for a month, sat front-row with brother David and mom Ricky.