Does the picture taken under bright also shows blue tint/color?
I am worried if thats the prorective film covering the camera thats damaged causing the blue light leak.
My advice would to bring your phone to your local Sony Center for inspection and evaluation.
http://support.sonymobile.com/global-en/xperiaz2/contactUs/The best application to take pictures in my opinion is VSCO Cam(with its filters) and Sony's very own 20MP snaps(used for taking crowd pictures of big events and functions)
Hope that helps
