Birdy Grey - SPENCE CONVERTIBLE DRESS - Silver Gray M

New with tags, not worn or altered, just tried on. The color is called Silver. It is a beautiful blue/gray. There is a small dark spot on the skirt. It is on the front at or below knee level. I don’t want to mess it up, so I did not try to treat the spot. Unsure of what it is. It came with it.