Rotating arm with Animation Event

I want to do the arm following the mouse, but a bit different. So I figured out that what I needed is an Animation Event. So I programmed the code and inserted the event and it doesn’t work! It’s a puppet character.

Transform Tree:

-Player
  -Body
    -Head
      -Face
    -Left Arm Upper
      -Left Arm Lower
        -Left Weapon
    -Right Arm Upper
      -Right Arm Lower
        -Right Weapon
    -Left Leg Upper
      -Left Leg Lower
    -Right Leg Upper
      -Right Leg Lower

Animator is on the Player.
I made a code into the PlatformCharacter2D, so it can show into the animator:

void AimLeftArm () {
		Vector3 difference = Camera.main.ScreenToWorldPoint (Input.mousePosition) - LeftUpperArm.position;
		difference.Normalize ();
		
		if (LeftUpperArm.transform.root.localScale.x == 1) {
			float RotZ = Mathf.Atan2 (difference.x, -difference.y) * Mathf.Rad2Deg;
			LeftUpperArm.rotation = Quaternion.Euler (0f, 0f, RotZ);
		}
		
		else if (LeftUpperArm.root.localScale.x == -1) {
			float RotZ = Mathf.Atan2 (difference.x, -difference.y) * Mathf.Rad2Deg;
			LeftUpperArm.rotation = Quaternion.Euler (0f, 0f, -RotZ);
		}
	}

But it doesn’t move the arm!

I just needed to add it to LateUpdate ()