Hi guys, I have some trouble with my kobo clara 2e.

Kobo doesn't provide repairing service in my country. I have to fix it by myself.
A few days ago, it fell from a bed about 60cm high. Then I noticed a serious ghost touch phenomenon. Now that I think about it, it seems that ghost touch had occurred before the falling, but the frequency was not high.
I have upgraded kobo clara 2e to the latest version (4.38.23429 25-8-18) and reset it. Also, I clear the screen with a brush. But still have the ghost touch on the upper left.