C# Bone Look-At not working :(

hi all,

i'm trying to get my characters head bone to look at the camera through C# but i'm not having much success:

 public class PlayerScript : MonoBehaviour {
    public GameObject mHead;
    public Transform target;

    void Start(){
       mHead = GameObject.Find("HeadBone"); 
    }

    void Update(){
       
       mHead.transform.LookAt(target);
 
  }
 }

any ideas as to what i'm doing wrong?

thanks