Saving highscore for each levels

I am having trouble with loading highscore using playerprefs.

This is what my highscore script looks like:

 // Use this for initialization
 void Start()
 {
     CurrentLevel = LevelLoader.FindObjectOfType<LevelLoader>().CurrentLevel;
     highscore = PlayerPrefs.GetInt("Level" + CurrentLevel.ToString() + "_score", highscore);
     text = GetComponent<Text>();
     Score = 0;
    
 }

 // Update is called once per frame
 void Update()
 {
             if (Score < 0)
             {
                 Score = 0;
             }
             if (Score >highscore)
             {
               highscore = Score;
               PlayerPrefs.SetInt("Level" + CurrentLevel.ToString() + "_score",highscore);
             }
     text.text = "" + highscore;
 }
 
 public static void AddPoints(int pointsToAdd)
 {
     Score += pointsToAdd;
 }

and this is the script i useed to get the highscore so i could use the score for 3-star rating system:

//Use this for initialization

void Start ()

 {

     high= PlayerPrefs.GetInt("Level" + CurrentLevel.ToString() + "_score", highScore.highscore);
     CheckCurrentLevel();
     PlayerInZone = false;
            
 }
 
 // Update is called once per frame
 void Update () {
   
     if (PlayerInZone)
     {
             AudioSource.PlayClipAtPoint(WinMenu, transform.position);
             PlayerPrefs.Save();
             Playerwin.SetActive(true);
         TimeManager.FindObjectOfType<TimeManager>().countingTime =100;
         SaveMyGame();

     }
     
 }
 void OnTriggerEnter2D(Collider2D other)
 {
     if (other.tag == "Player")
     {
         PlayerInZone = true;
         Debug.Log("GameEnd");
     }
 }
 void OnTriggerExit2D(Collider2D other)
 {
     if (other.tag == "Player")
     {
         PlayerInZone = false;
        
     }
 }

public void CheckCurrentLevel() {

     for (int i = 0; i < LevelAmount; i++)
     {
         if (Application.loadedLevelName == "Level" + i)
         {
             CurrentLevel = i;
             // PlayerPrefs.GetInt("Level" + CurrentLevel.ToString() + "_score", highscore);
         }
     }
 }
 void SaveMyGame()
 {
     int NextLevel = CurrentLevel + 1;
     if (NextLevel < LevelAmount)
     {
         PlayerPrefs.SetInt("Level" + NextLevel.ToString(), 1);

         PlayerPrefs.SetInt("Level" + CurrentLevel.ToString() + "_score", highScore.highscore);

     }
     else
     {

         PlayerPrefs.SetInt("Level" + CurrentLevel.ToString() + "_score", highScore.highscore);
     }
 }

I wish i could solve this because i don't know where the error lies