iOS 7 iPhone 5 white blotch on top left corner of Screen

I have noticed a white blotch appearing and disappearing since I updated to iOS 7 on my iPhone 5 64 GB. This happens at a few places:

1. opening the calculator app from control centre and closing it by pressing home button

2. opening and closing any apps by tapping on "open" from the AppStore update tab.

This is repeatable, I have not tried this on other iOS 7 devices so far but friends of mine have said that they haven't seen this. Has anyone else seen this happening on their phone? Is this a bug? Is there a fix?

Cheers!🙂