my screen is black on a LG Xenon?

Hi I have an LG xenon and i went for a run today with my phone. when i finished the screen was black. when i touch it, there is a back light but it shows nothing. i've tried taking the battery out and putting it back in but nothing happened except it is slow in the response to turn it back on. It also vibrates still when i touch the screen and the kekyboard lights up.