How to remove the circle gray spots in the screen of iPod?

OK. I have one of those gray spots. In fact, I had two, a large one (about the size of a penny) and a tiny one. They appeared after my 5 year old daughter sneaked a while with the ipod. I had accepted she should have hit the screen an so it was a dead spot. I could keep using te ipod, so I did nothing. Yet, after a few months, the small spot disappeared. So, the screen spot wasn't really a dead spot. It came back to live. Now, a month later, the large spot started to move on its own. It has moved almost a quarter of an inch. That is, a good part of the screen that I had assumed dead is now working perfectly well (I can now see the battery status, which I couldn't with the original spot location). Unfortunately, it is moving towards the center of the screen, rather than outwards, as I would like it to. I wonder if someone had seen this before, and whether there is a way to make it move the way I would like it to? It actually seems to be moving downwards, since te ipod is mostly standing on a charging cradle.

Those are dead spots in the digitizer. You are going to need to replace the screen assembly. You won't lose any files by doing this.

I've moved the grey spot around, there where tons of small ones on the screen after a sharp drop of my phone, then I started to move them around until a big grey dot has formed at bottom -left of screen, the size of home screen button, although I'm not able to push it out of the edge., ( the spots become more fluid like when heated, and solid and bit compressed when cooled, used a heat gun and fridge) any suggestions on pushing it out? I'm using iPhone 4,