Temperary Variables

Hi, so I want to create a variable that tracks the difference in rotation of my gun every frame. I am doing this so I can use this information in order to create a swaying effect. I am trying to set up a temporary variable that stores the rotation. It is then compared to the current rotation, and I get to find out the difference. However, it seems to always return 0. Am I setting this up wrong? Also, I know that the code does not add the sway yet, I just need it to get the difference first. Thanks!

 //Variables
 
 var tempRotation: Quaternion;
 var rotationDifferenceX: int;
 var rotationDifferenceY: int;
 
 
 //Script
 
 rotationDifferenceY = tempRotation.y - transform.rotation.y;        
     rotationDifferenceX = tempRotation.x - transform.rotation.x;    
     Debug.Log(rotationDifferenceX);
     Debug.Log(rotationDifferenceY);
     rotationTarget = cameraObject.transform.rotation; 
     
     rotationTarget.y += rotationDifferenceY;
     rotationTarget.x += rotationDifferenceX;
     
     transform.rotation = rotationTarget; 
     tempRotation = transform.rotation;