Shooting Gun C#

I’m at my wits end.

This was working before. Now its not. Why?

 {
        public GameObject shotSpawn;
        public GameObject shot;
        public float delayTime = 1;
        private float counter = 0;
    
        void Update()
    
        {
        if (Input.GetKey(KeyCode.Mouse0) && counter > delayTime)
            {
               
            }
            counter += Time.deltaTime;
        }
        void FireGun()
        {
            Instantiate(shot, shotSpawn.transform.position, shotSpawn.transform.rotation);
            GetComponent<AudioSource>().Play();
         }
    
    }

You’re code doesn’t do anything when you click the mouse…

if (Input.GetKey(KeyCode.Mouse0) && counter > delayTime)
{
                
}