I didn't even drop my tablet, yet there's a circle of water in the corner of the screen?

A

AC Question

I didn't even drop my tablet, yet there's a circle of water in the corner of the screen.

I have xperia tablet s and I have no history of dropping or spilling it with water. Then, one day I saw a circle of I think water in the upper right corner of my screen. I tried to lean it upside down so it can move outside yet it only changes shape. Now the cloud around it is getting bigger. Then later on, there's a cloud now also in the upper left corner. I don't know why. It's still working though even if I touch. I tried putting it in a rice and still no effect. Help me please. I can't find any ways to resolve this.