Took flagyl and levoquin for 10 days. developed white coating on tongue. been on nystatin for 8 days and tongue still white. how long till white gone?

Maybe a couple weeks: Coated tongue can be due to yeast or fungus, which can be triggered by broad spectrum antibiotics like the ones you took. However, most white coated tongues aren't due to fungus. Simply being ill or on antibiotics can do it. You should contact the doc who is treating you. Most likely s/he will advise you to sit tight and let it clear up on its own, which might take a few weeks. No harm will come.