[Quiet Man Cometh]

Your best bet would probably have been a spray or something like Nature's Miracle that's designed for urine, if that's what it was. You can't really wash a mattress, but steam might be an option. Anything damp would dry eventually. Ideally, put a fan or something in the room. If there's mold though, you have a problem. Get a new one. For the future, get a mattress cover that goes under the sheets that you can just through right in the washer.