GUI.Label not updating image

The health bar has 20 states so I use math.round to find the nearest image to load. I assign the textures in the inspector and I know the script can access it because it works for the initial load but doesn't update thereafter. The code seems to be spot perfect and I can see the healthBar variable that stores the texture changing but the GUI.Label that is getting its image from this variables don't change properly. For example if I set my code to different values beforehand in the code or in the inspector the health bar updates the image properly when I play but it will never change after that even though I can see the healthBar variable updating that the method derives from changing to the right image.

 using UnityEngine;
 using System.Collections;
 using System.Collections.Generic;
 public class PlayerControl : MonoBehaviour {
     public int health;
     public int i;
     public List<Texture2D> textures = new List<Texture2D>();
     public Texture2D healthBar;
     // Use this for initialization
     void Awake () 
     {
         health = 10;
         i = 2;
 
     }
     
     // Update is called once per frame
     void Update () 
     {
         if ( health < 0)
             Application.LoadLevel(Application.loadedLevel);
         i =    Mathf.RoundToInt(health / 5);
 
     }
     void OnGUI ()
     {
         healthBar = textures[i];
         GUI.Label(new Rect(0, -50, 128, 128) , healthBar);
     }
 }