Try bouncing hot shower spray off a wall so the mist gets your cham. I have never tried taking my cham in the shower, but I know others have had great results. If you have a plant that can tolerate the shower and its safe for your cham of course, it should work fine. Or you can put hot water in a spray bottle and mist that way.
a good way to get around being bitten (if that is your problem is to put on some sort of glove. Mine started to his and look like he was tryin to bite me . but after a good few times of him realizing he is not goin to win . he now doesn't try too . .
what i do is hang a fake plant from the top and let him just sit on it . he wont go anywhere and he wont fall . then i turn the water on (not on him) but keep it warm . i put it at the temperature that i like my showers at. They like the warmth . so, i dont see using that temperature being a bad thing .
About ur lizard, I cannot say whether they do or do not like being in the shower, or if it is a good thing for that species... but personally i would think it would be fine.. they all like the humidity . all species
From my limited personal experience with Fischers, but from hearing over and over again from other keepers, This species is best kept if left alone and content by itself in luscious green densely planted cages.
For showering chameleons I find that a thick Shefflera (Umbrella plant) does best. From time to time I add some nice Driftwood to allow them to escape the water if they need.