Hi Ady791,
I believe there may be some damage on the screen (which is usually not covered under normal warranty until you are entitled for accidental damage coverage). It may also be possible that during travelling or commuting, the laptop in the bag might have suffered some pressure exerted on the back cover which might lead to internal screen / LCD damage.
Are you still able to see the patches on the screen or is the screen behaving as normal? If patches do arise, I would recommend to post a couple of pictures here of the LCD / screen so that we can reach a decisive conclusion.
