I don't think nystatin is that gross... it does look like egg yolks, but it's not thick... just real sweet. I'm taking it now for thrush although I'm not sure that's what I have at this point. If you do have thrush, your tongue would probably be white and you might have white spots inside your mouth, too.
It would probably help to brush and scrape your tongue, too, even if you don't have thrush. I figure that when you're flaring, your whole digestive tract is irritated, and it's probably likely that there would be a less that pleasant odor from all that intestinal turmoil.