Can't access variable from another script

When a player catches boost(additional life) I want to access my health script and add +1 to the currentHealth. It doesn't work. Here my boost life script:

     public GameObject particles;
     public bool isOnTrigger = false;
 
     void OnTriggerEnter (Collider other) {
         if (other.tag == "Player") {
             GameObject.FindWithTag("Player").GetComponent<PlayerHealth>().currentHealth+=1;
             GameObject part = Instantiate(particles,transform.position,Quaternion.identity)as GameObject;
             Destroy(part,2);
             Destroy (this.gameObject);
         }
 
     }
 }

This is HealthScript attached to the player:

 public int currentHealth;
     private int startHealth = 7;
     private GUIStyle styleForHealth;
     private GUIStyle healthBarBG;
     private float healthBarLength;
     private bool showHealthBar = true;
 
 
     void Start(){
         currentHealth = startHealth;
     }
 
     void Update () {
         var scoreScr = Camera.main.GetComponent<ScoreScript> ();
         currentHealth = startHealth - scoreScr.miss - scoreScr.crush;
 
         if (currentHealth > startHealth)
             currentHealth = startHealth;
         if (currentHealth < 0)
             currentHealth = 0;
         if (currentHealth<1) {
             GameObject.FindWithTag("Player").GetComponent<PlayerController>().canControl = false;
             Invoke ("LevelStart", 2);
         }
         healthBarLength = ((Screen.width / 4 ) /startHealth)*currentHealth;
         if (healthBarLength < 1) {
             showHealthBar = false;
             healthBarLength = 0;
         }
     }
 
     void LevelStart(){
         Application.LoadLevel (2);
     }
     void OnGUI(){
         InitStyles();
         GUI.Box (new Rect(Screen.width/2+195,10,Screen.width/4+10,30),"  ",healthBarBG);
         if(showHealthBar)
             GUI.Box (new Rect(Screen.width/2+200,15,healthBarLength,20),currentHealth+"/"+startHealth, styleForHealth);
 
     }
     private void InitStyles(){
         if( styleForHealth == null ){
             styleForHealth = new GUIStyle( GUI.skin.box );
             styleForHealth.normal.background = MakeTex( 2, 2, new Color( 0.4f, 0.8f, 0f, 1f ) );
         }
         if (healthBarBG == null) {
             healthBarBG = new GUIStyle(GUI.skin.box);
             healthBarBG.normal.background = MakeTex(2,2, new Color(0f, 0.4f, 0f, 1f) );
         }
     }
     private Texture2D MakeTex( int width, int height, Color col ){
         Color[] pix = new Color[width * height];
         for( int i = 0; i < pix.Length; ++i ){
             pix[ i ] = col;
         }
         Texture2D result = new Texture2D( width, height );
         result.SetPixels( pix );
         result.Apply();
         return result;
     }

Thank you in advance.