Ouch -- plasma tv permanent burn-in?

[Mogul]

I hadn't even noticed this until a couple of days ago, but my 42 inch plasma seems to have had some kind of permanent burn-in. You can only see it if a scene is completely black but, let me try to describe it. You know how when you're not watching a widescreen movie or show, and the 4:3 bars are on the left and right sides? OK, "coming out" of where the right black bar ends, is this sort of blotch of light. It's kind of yellowish... sort of. It's hard for me to describe, other than to say it's discolored slightly when the rest of the screen is black.

I have tried leaving the tv on overnight with just a snowscreen, but that didn't fix it, as it would any normal burn-in. I have also tried my tv's built in white wash feature multiple times, but with no effect. The good thing is that it doesn't seem to affect anything on the screen at all when I'm watching a movie or whatever. There probably is a very, very slight difference in color, but I honestly can't even begin to tell, if there is. So I can live with this, but I would like to know if it can be repaired.

Soooo it looks like I have screwed up my tv permanently. Any suggestions?