Top of the screen does not respond to touch?

I took my Xperia Z2 to vacation with me. I took a few photos underwater (pool), not too deep tho, the problem was when I came back, a week later the top of the screen didnt recognize the touch, just right in the notification area, it is the rectangle on the top about 1 inch so I cant check my notifications unless I turn the phone, and this is becoming so annoying. I ran the test for the screen and indeed it does not recognize the top of the screen. I read in a LG G2 forum that sometimes this happened and it was because some cables were disconnected. I dont know if this problem can happen in the Z2 but I wanted to ask if someone had this problem and how did you solve it, otherwise I could buy a replacement, they are about $80 but I rather connect the cable. The LCD is fine, the only thing that doesnt work is the top of the touch. Thanks in advance and sorry for my english.