Look at the post "Bad Breath", by Jenna, and last commented on on 6/11.
I don't mean to give the 'easy' answer to your tongue question, but I think it warrants it in this case. JMO, but I think you need a complete physical by your MD. Perhaps someone else knows better, but I seem to recall that this could be an indicator of a non-dental medical problem. I'm NOT a doctor, so please take what is just my opinion with a grain of salt, ok? If no one else answers you, you might try asking the question on a different Health Board.