BF4 - Black dot in top left corner of screen (not a dead pixel)

I recently noticed a small black dot in top left of the screen, it's about two pixels wide and two pixels high. It's only there when playing as if i press escape to go to the menu the screen looks normal again and theres no dot. I know it's not a dead pixel as like i said the dot goes and its only there while in a game in bf4.. if i do anything else there is no dot.