Help my phone screen is all weird?

[J.P]

My phone screen has gone all weird its like got little patches of green on it but you can see threw the patches of green if you get what i mean. I can still use it and everything i just want to now whats wrong with it. It happened last night, I got into the car and i went on msn, saw who was on then signed out then i put it on the car seat but i wasn't sitting on it then i looked at it a few minutes later and it went all weird. I turned it off and turned it back on, took the battery out then put in again and then i took the battery and the sim out put them back in and none of them worked. So if you now whats wrong with it please help cause i cant live without phone.