I don't know what finish is used, possibly nitrocellulose. There is a way of getting a clue here;
http://www.frets.com/FretsPages/Luthier ... etest.html
There is also a method of using laquer retarder shown, to remove some blushing. I'm not sure that it would work on a thick and well cured finish.
Its hard to understand why the blushing is showing up now. As lux says its usually moisture trapped in the finish.
If its a really good guitar it might be worthwhile trying to correct the fault. If its just a modest guitar, it won't do any more harm to just leave it as it is.
"When I was younger, I could remember almost everything, whether it happened or not." Mark Twain