Input.GetMouseButtonDown() slow on mobile

I'm making a game that requires a lot of screen tapping, done very quickly. I noticed the game works fine in editor but, when I test on mobile, it slows down.

So, what is my problem exactly? When I'm tapping with 2 fingers, never at the same time but very quickly, it seems as if there is a bit of input lag. For each tap, my character sprite changes but, you can tell sometimes it takes a second to update the sprite and score. Works great in editor though.

I'm really hoping there is a way to fix this because otherwise, I'll need to switch to an engine that can handle the amount of tapping needed.

Here is my code:

 using UnityEngine;
 using System.Collections;
 using UnityEngine.UI;
 
 public class GameController : MonoBehaviour
 {
     public Sprite jim1; // Char sprite 1
     public Sprite jim2; // Char sprite 2
     public int touchCount; // Amount of touches
     public int colorTimer;
     public GameObject cameraParent; // Camera Parent
     public GameObject spaceBackground;
     public SpriteRenderer sr; // Char sprite renderer
     public Material spaceMaterial;
     public Text scoreText; // Score text
     public Text timerText; // Timer text
 
     private bool canTap; // self explanatory
     private float timer; // Countdown timer
     private Color ranColor; // Random color
     private Color spaceColor;  // Random space color
 
     // Use this for initialization
     void Start()
     {
         timer = 60f; // Game timer
         colorTimer = 30; // Color timer for the space background
         touchCount = 0; // Setting touchcount to 0
         sr = gameObject.GetComponent<SpriteRenderer>(); // Getting the sprite renderer and storing it in a variable
         spaceMaterial = spaceBackground.GetComponent<MeshRenderer>().material; // Getting the mesh renderer material and storing it in a variable
         scoreText.GetComponent<Text>(); // Getting the text componet
         canTap = true;
     }
 
     // Update is called once per frame
     void Update()
     {
 
         if (timer >= 0f) // If time is still remaining, count down
         {
             timer -= Time.deltaTime; // Taking 1 away every second
         }
         else {
             timer = 0f; // If there is no time remaining, set the timer to 0
             canTap = false;
         }
 
         timerText.text = Mathf.RoundToInt(timer).ToString(); // Rounding the float and then setting the timerText text value to the timers value
 
         if (touchCount % 2 == 0) // Checking if touchcount is even or odd. If even, the sprite will be set to jim1.
         {
             sr.sprite = jim1;
         }
         else {
             sr.sprite = jim2;
         }
 
         if (touchCount >= 50)
         {
             cameraParent.transform.position = Random.insideUnitSphere * 0.1f; // screenshake baby
         }
 
         if (touchCount >= 200)
         {
             transform.Rotate(Vector3.forward * Time.deltaTime * 150);
         }
 
         if (touchCount >= 250) {
             gameObject.GetComponent<Animation>().enabled = true;
         }
 
         if (Input.touchCount > 0 && Input.GetTouch(0).phase == TouchPhase.Began && canTap) // Getting screen touches and setting to score
         {
            
             touchCount++; // adding to the touchcount
             scoreText.text = touchCount.ToString();
         }
 
         if (touchCount > 100)
         {
             colorTimer -= 1; // Take away 1 every frame
        
             if (colorTimer <= 0)
             {
                 ranColor = new Color(Random.Range(0f, 1f), Random.Range(0f, 1f), Random.Range(0f, 1f)); // Making a new color using random values
                 sr.color = ranColor; // setting the sprites color to the random color
                 spaceColor = new Color(Random.Range(0f, 1f), Random.Range(0f, 1f), Random.Range(0f, 1f), 1f); // Taking the random color and making it negitive
                 colorTimer = 30; // Resetting the timer
                 spaceMaterial.color = spaceColor;
             }
 
         }
     }
 }

ISSUE STILL NOT RESOLVED I think the best way to describe my issue would be, it feels like a few frames are being skipped every 7 taps or so. So, for example, each time I tap my sprite changes but, on that 7th tap, the sprite doesn't change.