Is the camera also blurred when using a third-party app, such as Messenger, Snap Chat, or any other camera app? Some of these steps may help. https://www.samsung.com/us/support/troubleshooting/TSG01001297/ However, if the issue persists, I would recommend having the phone evaluated by a certified technician.
For service options in the U.S., please send a private message with the full model code and the IMEI number of the phone. http://bit.ly/2XERsky
For service outside the U.S., please follow this link: https://www.samsung.com/us/common/visitlocationsite.html