White spots on my ipod touch screen?

They look like just a smudge of something, but whenever I try to clean them off, nothing happens. I even scratch lightly with my finger nail and still nothing happens.
It didn't come with these on it, and it appears that they're inside the screen.
They're not dead pixels ( I know what those look like).
Since it's impossible to get a smudge of something inside the screen, I thought maybe something was wrong with my screen? Like a layer of it might of cracked or something (I'm REALLY hoping this is not the case). But they seem to get to be more. They're very small, and are still there when the screen is off, but are really noticeable when the screen is on.
Any ideas what the problem is or how to fix it?
 
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