How to have a score counter increment in OnTriggerEnter

Hello I am trying to get a score counter going when one object passes through an empty object. Below is the code I am using.

 private void OnTriggerEnter(Collider other){
     var collider = projectile.gameObject;
     score = score+1;
    // Debug.Log(collider);
     Debug.Log(score);
 }

The score increments when the projectile passes through the object but if i shoot a second one, the score wont increment again, until the first projectile rolls back through and it goes to two.

What I would like to know is how to destroy the object after one second of passing through the empty object, increment the score by one while storing that score, also allow another object to pass through and repeat the previous steps but incrementing the score to 2 and so on.

Any help would be appreciated