How to access my highscore from another scene ?

i want to access my highscore from another script and another scene to my current scene so that i can make a scoreboard link with facebook. But the problem is that i always get my highscore as zero.
This is my facebook script ,(check “public void SetScore”)

'using UnityEngine;
using UnityEngine.UI;
using System.Collections;
using System.Collections.Generic;

public class FBholder : MonoBehaviour {
	
	public GameObject UIFBIsLoggedIn;
	public GameObject UIFBNotLoggedIn;
	public GameObject UIFBAvatar;
	public GameObject UIFBUserName;
	private List<object> scoresList = null;

	public GameObject ScoreEntryPanel;
	public GameObject ScoreScrollList;
	
	private Dictionary<string, string> profile = null;
	
	void Awake()
	{
		FB.Init (SetInit, OnHideUnity);
	}
	
	private void SetInit()
	{
		Debug.Log ("FB Init done.");
		
		if(FB.IsLoggedIn)
		{
			DealWithFBMenus(true);
			Debug.Log ("FB Logged In");
		}else{
			DealWithFBMenus(false);
		}
		
	}
	
	private void OnHideUnity(bool isGameShown)
	{
		
		if(!isGameShown)
		{
			Time.timeScale = 0;
		}else{
			Time.timeScale = 1;
		}
		
	}
	
	public void FBlogin()
	{
		FB.Login ("email,publish_actions", AuthCallback);
	}
	
	void AuthCallback(FBResult result)
	{
		if(FB.IsLoggedIn){
			Debug.Log ("FB login worked!");
			DealWithFBMenus(true);
		}else{
			Debug.Log ("FB Login fail");
			DealWithFBMenus(false);
		}
	}
	
	void DealWithFBMenus(bool isLoggedIn)
	{
		if(isLoggedIn){
			UIFBIsLoggedIn.SetActive (true);
			UIFBNotLoggedIn.SetActive(false);
			
			// get profile picture code
			FB.API (Util.GetPictureURL("me", 128, 128), Facebook.HttpMethod.GET, DealWithProfilePicture);
			FB.API ("/me?fields=id,first_name", Facebook.HttpMethod.GET, DealWithUserName);
			// get username code
			
		}else{
			UIFBIsLoggedIn.SetActive (false);
			UIFBNotLoggedIn.SetActive(true);
		}
	}

	
	void DealWithProfilePicture(FBResult result)
	{
		
		if(result.Error != null)
		{
			Debug.Log ("problem with getting profile picture");
			
			FB.API (Util.GetPictureURL("me", 128, 128), Facebook.HttpMethod.GET, DealWithProfilePicture);
			return;
		}
		
		Image UserAvatar = UIFBAvatar.GetComponent<Image>();
		UserAvatar.sprite = Sprite.Create (result.Texture, new Rect(0,0,128,128), new Vector2(0,0));
		
	}
	
	void DealWithUserName(FBResult result)
	{
		if(result.Error != null)
		{
			Debug.Log ("problem with getting profile picture");
			
			FB.API (  "/me?fields=id,first_name", Facebook.HttpMethod.GET, DealWithUserName);
			return;
		}
		
		profile = Util.DeserializeJSONProfile(result.Text);
		
		Text UserMsg = UIFBUserName.GetComponent<Text>();
		
		UserMsg.text = "Welcome, " + profile["first_name"];
		
		
	}
	
	public void ShareWithFriends()
	{
		FB.Feed (
			linkCaption: "I'm playing this awesome game",
			picture: "http://i58.tinypic.com/vqhdts.png",
			linkName: "Check out this new game",
			link: "http://apps.facebook.com/" + FB.AppId + "/?challenge_brag=" + (FB.IsLoggedIn ? FB.UserId : "guest")
			);
	}
	
	public void InviteFriends()
	{
		FB.AppRequest(
			message: "I challenge you to beat my score.",
			title: "Challenge your friends. "
			);
	}
	
	// All Scores API related Things
	
	public void QueryScores()
	{
		FB.API ("/app/scores?fields=score,user.limit(30)", Facebook.HttpMethod.GET, ScoresCallback);
	}
	
	private void ScoresCallback(FBResult result)
	{
		Debug.Log ("Scores callback: " + result.Text);
		
		
		scoresList = Util.DeserializeScores (result.Text);
		
		foreach (Transform child in ScoreScrollList.transform) 
		{
			GameObject.Destroy (child.gameObject);
		}
		
		foreach (object score in scoresList) 
		{
			
			var entry = (Dictionary<string,object>) score;
			var user = (Dictionary<string,object>) entry["user"];
			
			
			
			
			GameObject ScorePanel;
			ScorePanel = Instantiate (ScoreEntryPanel) as GameObject;
			ScorePanel.transform.parent = ScoreScrollList.transform;
			
			Transform ThisScoreName = ScorePanel.transform.Find ("FriendName");
			Transform ThisScoreScore = ScorePanel.transform.Find ("FriendScore");
			Text ScoreName = ThisScoreName.GetComponent<Text>();
			Text ScoreScore = ThisScoreScore.GetComponent<Text>();
			
			ScoreName.text = user["name"].ToString();
			ScoreScore.text = entry["score"].ToString();
			
			Transform TheUserAvatar = ScorePanel.transform.Find ("FriendAvatar");
			Image UserAvatar = TheUserAvatar.GetComponent<Image>();
			
			
			FB.API (Util.GetPictureURL(user["id"].ToString (), 128,128), Facebook.HttpMethod.GET, delegate(FBResult pictureResult){
				
				if(pictureResult.Error != null) // if there was an error
				{
					Debug.Log (pictureResult.Error);
				}
				else // if everything was fine
				{
					UserAvatar.sprite = Sprite.Create (pictureResult.Texture, new Rect(0,0,128,128), new Vector2(0,0));
				}
				
			});
			
			
			
		}

		
	}
	
	**public void SetScore()
	{
		GameObject High = GameObject.FindGameObjectWithTag("Score");
		ScoreController scoreController = High.GetComponent <ScoreController>();
	
		int high = scoreController.HighScore;
		var scoreData = new Dictionary<string,string> ();
		scoreData ["score"] = high.ToString();
		FB.API ("/me/scores", Facebook.HttpMethod.POST, delegate(FBResult result) {
			Debug.Log ("Score submit result: " + result.Text);
		}, scoreData);
	}**
	
	
}`

And this is my scoreController script in another scene

using UnityEngine;
using System.Collections;
using UnityEngine.UI;

public class ScoreController : MonoBehaviour {

	public Text ScoreText;
	public int score;
	private int Count = 2;
	public Text TotalScoreText;
	public Text HighScoreText;
	public int HighScore;


	void Start () 
	{
	
		score = -2;
		UpdateScore ();
		AddScore ();        
	}
	
	public    void UpdateScore() 
	{
		ScoreText.text = "Score: " + score;
		TotalScoreText.text = "TOTAL SCORE -: " + score;
		HighScoreText.text = "HIGH SCORE -: " + HighScore; 
	}
	
	public void AddScore( )
	{
		score += Count;
		if(score>PlayerPrefs.GetInt ("HIGHSCORE_KEY",0))
		{
			PlayerPrefs.SetInt ("HIGHSCORE_KEY",score);
		}
		HighScore = PlayerPrefs.GetInt ("HIGHSCORE_KEY",0);
		UpdateScore ();
	}






}

DontDestroyOnLoad(); will stop a gameobject from being destroyed during a scene transition. You could also use a static variable.