Dark spots on iPhone 4 screen.

Hello!

My iPhone 4 recently started developing these strange shadow-like dark spots on the bottom of the screen. This seems odd to me as I the phone hasn't come in contact with any water. But just in case, I left it in a bag of rice for a couple of nights but to no luck, the spots have not changed. The spots are only noticeable when on a whitemp background so it isn't a big deal, but it can be annoying at times. Please reply when possible! 🙂

here is an image of the screen -\/-\/-\/-\/- ℹ

http://tinypic.com/r/29crint/8