I've had geographic tongue for several years, usually mild, sometimes
flaring more painfully.  I have no cure to offer, and nobody seems to
know the root cause.  But I have found a simple treatment that helps
provide relief from the symptoms and reduce the inflammation.

Pour a tablespoon or so of Biotene mouthwash [http://www.laclede.com]
in a cup.  Open a capsule (not a tablet) of Benadryl
[http://www.benadryl.com] or generic diphenhydramine, and pour the
powder in contains into the mouthwash.  (Discard the empty capsule.)
Swirl the cup to dissolve the powder.

Now rinse your mouth with the resulting solution, for 10 or 15 minutes.
I usually do this in the shower in the morning, and while reading
before retiring in the evening.  The Benadryl numbs your tongue, a
welcome relief during a flare-up.  After spitting out the solution,
avoid drinking or eating for a while.

While this treatment doesn't make geographic tongue go away entirely,
it seems to suppress it, at least for me.

FYI, I've tried rinsing with water-based saline solution, Benadryl
solution in water, and plain Biotene mouthwash without Benadryl.  None
of these were as effective for me.

If this treatment works for you, or if you have other suggestions, I'd
welcome hearing from you.

Sincerely,
Larry Lang