Spider crack on my Macbook Air out of nowhere!

I turned off my laptop and I placed it down carefullying on my desk. A couple of hours later I come back and I turn it on, I notice this crack and I started start freaking out. I couldnt have been more careful with it ! I treat it like its my baby ! The crack is isnt even on the outside of the glass because you can't feel the crack or see it when my laptop is off. It has to be on the inside because you can only see it crack when the laptop is turned off.If i had cracked it, the crack would be on the inside. I put no pressure on it. The crack looks like a spider, it looks like a daddy long legs. The crack is on the bottom right. The crack actually really bothers me and I am really ticked off right now. I am the only one who uses this laptop and like I said I treat it like a baby. I dont know what to do.....