Adding a life on collision, otherwise subtract

Hello everybody,

I typed a really long question and realized it was boring, so this is a summary:

• My enemy has two hitpoints.

• if it dies it instantiates a particle system

• It can happen you only hit it once

• Enemy must be destroyed at some point if you failed to shoot it twice

• Enemy collides with my box which should destroy it, showing a different particle

• Because of collision, 1 hitpoint is subtracted, therefore now showing 2 particle systems

• Tried adding life on specific collision so it doesn't show first particle system

• Doesn't work

I attached this script to my enemy:

 function OnCollisionEnter (collision : Collision){
     life --;
     if(life == 0){
     Destroy(target);
     Instantiate(RedBurst2, transform.position, transform.rotation);
     Instantiate(plusone, transform.position, transform.rotation);
         audio.PlayOneShot(AUW);
         
     }
     if(collision.gameObject.tag == "border"){
     life++;
         Destroy(zombie);
         Instantiate(RedBurst, transform.position, transform.rotation);
         Instantiate(minustwo, transform.position, transform.rotation);
     }
 }

I left out the vars, they speak for themselves. Can someone point out the error? I feel like it's something really stupid.

Thanks!