Few days ago, my filiform papillae became quite long. My mouth was feeling dry for the past 2 weeks as well. I started brushing my teeth twice a day, drink a lot of water and started eating crunchy food. The filiform papillae close to the tip of the tongue went back to normal quite fast, the others didn't. However, today the papillae close to the tip are elongated again. Why the hairy tongue doesn't go away?