I think the main component of HT IS the fact that the body is too acidic. I recently visited my ENT doctor for this condition and he said that my acid levels in my stomach were too high. Also, I came across this forum on this website as well, here is the link:
https://www.healingwell.com/community/default.aspx?f=45&m=308557
The persons 13 year old daughter had hairy tongue and was given pepcid which is an acid reflux and was cured of this condition. After all the research throught years of having this condition, I have now came to a conclusion that treating the mouth alone isn't going to cure this. Change in diet as 23healthy said, basically eating more alkaline foods than acidic foods (green veggies and many other alkalizing foods). I recently started going to the gym and I bought alkaline drops where i add about 20 - 25 drops in my 1L bottle of water (which makes the water really alkaline) and i drink about 2 -3L a day. I'm going to try and take Pepcid but i'm not sure if its over the counter or rx.