I've never had this occur, but I'd hesitate applying a leather conditioner before getting all of the stain out first. What did you use to clean it? I don't actually know the answer, but I would contact a leather care specialist (my local shoe repair guy knows a lot about leather, stains, and products in general, as well as a lot of years of experience). Barring that, you can contact your retailer or BV directly and inquire, too, though going through BV might take a few days or longer to get a proper response.