Android Screen Press Detection

I am trying to build an app that detects if a user puts their lips on the screen. How could I get an image of their lips when they put it on the screen?

Is there possibly a way to get a grid of the screen and then determine where th开发者_开发百科ey were placed?

Multi-touch support depends on the version of Android. You need at least 2.0. I understand that Android in principle supports up to 256 "fingers" at once, but I'm currently playing with it and my HTC Desire supports 2 fingers. I don't think what you're after will be possible on many devices, if any.