I loose health after touched enemy and my script only displays the first bloodimage

How do I fix so that if my enemy just touched me and stays out I'll regenerate instead of dying. And I'm trying to fix my healthgui. Help please? [Note: It's an edited script from speed tutor's fading health]

 #pragma strict
 
 var tex1 : Texture;
 var tex2 : Texture;
 var tex3 : Texture;
 var tex4 : Texture;
 var tex5 : Texture;
 var style : GUIStyle;
  
 var health : float = 100.0;
  
 private var dead : boolean = false;
 private var maxHealth : float = 100.0;
 private var enterCollider : boolean = false;
  
 var damagePerSecondOnContact : float = 20;
 var healthRegeneratedPerSecond : float = 5;
  
  
 //Damage Collider
 function OnTriggerEnter(Col : Collider) {
     if (Col.gameObject.tag == "Enemy") {
        enterCollider = true;
        Debug.Log("Is inside collider");
     }
 }
  
 function OnTriggerExit(Col : Collider) {
     if (Col.gameObject.tag == "Enemy") {
        enterCollider = false;
     }
 }
  
 function Update() {
  
     if(dead){
        health = 0;
        return;
     }
  
     //check for health exceeding maxHealth and correct if needed
     if (health > maxHealth) {
        health = maxHealth;
     }
  
     if (health > 0) {
        //We are alive! Check if we should heal or take damage
        if(enterCollider == true){
          //take damage
          health -= Time.deltaTime * damagePerSecondOnContact;
          Debug.Log("Was damaged to " + health);
        }
        else{
          //heal (a heal delay might be good, we may be regenerating faster than collisions can cause damage)
          health += Time.deltaTime * healthRegeneratedPerSecond;
          Debug.Log("Was healed to " + health);
        }
     }
     else if (health <= 0) {
        StartCoroutine(OnHealthZero()); //THIS WAS WHAT WAS MISSING
     }
 }
  
 function OnGUI() {
     
     if (health <= 70) {
        GUI.DrawTexture(Rect(0, 0, Screen.width, Screen.height), tex1);
     }
     else if (health <= 45) {
        GUI.DrawTexture(Rect(0, 0, Screen.width, Screen.height), tex2);
     }
     else if (health <= 25) {
        GUI.DrawTexture(Rect(0, 0, Screen.width, Screen.height), tex3);
     }
     else if (health <= 10) {
        GUI.DrawTexture(Rect(0, 0, Screen.width, Screen.height), tex4);
     }
     else if (health <= 0 || dead) {
        GUI.DrawTexture(Rect(0, 0, Screen.width, Screen.height), tex5);
     }
     GUI.Box  (Rect (Screen.width - 200,Screen.height-35,200,80), health.ToString(), style);
 }
  
 
 function OnHealthZero(){
 
     //we indicate that the player died IMMEDIATELY so as to stop bad updates
     Debug.Log("Is dead now");
     dead = true;
     yield  WaitForSeconds(0.01);
     Application.LoadLevel("Deade");
     }