The screen on my macbook is dark?

A few weeks ago the screen on my macbook switched to a negative image, I figured out how to remove the negative look but once I changed it back to %26quot;normal%26quot; my screen is still dark, the brightness is turned all the way up so I know thats not what it is, it just looks like a weird tint over my screen, does anyone know how to turn it back to the normal brightness? (i'm hoping its not a bulb burning out or something)