iOS 8.0.2 messed up my iPhone 5s
Jash, you can downgrade your OS to 8.0 by downloading the original IPSW file for your device.  (They are device specific, so make sure you have the model number handy for your phone.)  

http://www.redmondpie.com/ios-8-beta-download-release-date-features-rumors-and-news-update/

Once you download the version of 8.0 for your iPhone version - following this:

Connect iPhone to computer
Click on iPhone, then Summary
Hold SHIFT and click on restore. A file dialog window should open, allowing you to manually select the restore media. Navigate to where you downloaded the iOS software to, and select that .ipsw file from the list.  This is different for Mac vs. Windows - so it may be CNTRL or SHIFT for you. (SHIFT is Mac OS.) 

It should overwrite and install the 8.0 version to the iPhone.

Regards,

Ed