If it's a line on the bottom of your LCD, then 'burnt' would be a strong word. I've seen this occur before, but only within certain apps/environments. Turn off the phone for a while, then turn it back on. If the symptoms persist, the most you would need to be concerned about is an LCD replacement.

Please note that without a photo/screenshot, it's difficult for anyone to make even a plausible diagnosis of your problem. Start with that first.

Thanks