For a long time I have had a horrid looking tongue surface  whitish
green and have been given Chinese Herbs to boil up with the juice
drunk daily. I am supposed to have "damp" kidneys.  What does that
mean?  Orthodox medicine cannot help it seems, and I have almost given
up as the Chinese herbs taste horrible.

Fungal infection? You could try using Nystatin orally; talk to your
MD. Also try to brush your tongue gently with a soft tooth brush. An
over-the-counter remedy often used is rinsing your mouth with a
diluted 3% solution of hydrogen peroxide.

http://www.nlm.nih.gov/medlineplus/druginfo/uspdi/202417.html

Please read the disclaimer below, I am not an MD or health
professional. (But I've had a white tongue, and cured it with
nystantin:)