I had the same thing happen to mine after I put my fermentor in a bath tub filled with water. The little color stripes turned gray and looked ruined. I transfered the beer a couple weeks ago and figured I'd just buy a new fermometer. Just took a look at it after seeing this thread. I still have a couple spots that look grey, but most of it is back to normal.
It looks like it's reading the temperature correctly, so I guess it'll be ok.
Put your fermentor somewhere dry for a while and it may fix it. Worst case they don't cost much to replace.