Is this normal for at-home teeth whitening trays?

After just one 45-minute session with the at-home Aqua-fresh trays for sensitive teeth, I have three or four bright white blothes on my front teeth. Not big, but not unnoticeable, you know? My teeth have always been slightlyyellow, but that was better than beinty. Will this go away if I stop using the whitening trays, does anyone know?