Eeek, help. My 3 yr old DS decided to chew a felt tip when I was momentarily distracted and managed to get it all over his face. He also managed to get it on his teeth and now one of his front teeth is stained a mucky looking greyish blue. It won't brush off so I'm wondering if any of you have any suggestions on what I can do. They were cheapish ones from Asda so I'm wondering if this is part of the problem. Thanks!