Several weeks ago a darker spot appeared on my screen (as seen in the attached picture, it's right under the "Super User" tab) and it looks as if there was some liquid behind the screen. When I physically press it, it doesn't change its shape and it didn't change its shape since it appeared (around 2 weeks ago). The spot is visible especially on white background and is very weak with black background.
I tried blowing hot air on it and rubbing strong magnet (from a hard disk) but neither helped nor made it change its shape.
Do you have any ideas what could have caused it? Additionally, do you know how could it be fixed besides using my warranty? The laptop is 4 months old, Asus UX530UQ.