Mouth Infection

I noticed yesterday that my axolotl's mouth was "stuck" slightly agape. It has since become clear (due to increasing inflammation and discoloration around the mouth) that he has developed some sort of infection. His behavior hasn't much changed and he will still try to eat. I'm moving him to the fridge for the time being. The picture linked to below was taken a full day after I first noticed something was wrong and I'm afraid of the problem worsening quickly...is it time to make an appointment with my vet? Could this this an example of stomatitis / mouth rot? I've done a major water change each of the last 2 days...should I be worried about his tank mate? Both axies are about 2.5 y/o. My axie has had a clean bill of health up until now and I'm really worried! Any advice from experienced axie owners / enthusiasts would be greatly appreciated.

picture:

http://i29.tinypic.com/2lcpem0.jpg

Was sand the only substrate you had?
Also, are there/were there any snails in with your axies?

Yes, the sand is the only substrate, and no -- he's never had non-axoltl tank mates.

I think a visit to the vet would be best.

Oooh...poor thing. Watch him eat, see if it seems painful to him or gets in the way of eating.
Find a vet that has experience with exotic pets, definitely the best choice.

I definitely recommend a vet as stated. Let us know how it goes!