Iphone 4s touch position error after update 8.3

I use the iphone 4s, but there is a problem after I update to iOS version 8.3 on June 2, 2015.

After I update using itunes, when typing the keyboard will squeeze itself rather than on location.

Not only that, when I type a pass code, by itself would be typing at random.
When in the home menu, sometimes by itself open safari app.

.

before I update to version 8.3 is 8.2 such problems do not occur.

is there any way to fix it? or is it possible to downgrade to version 8.2 again?

sorry about my english.

Thanks