Swipe screen for mobile

I’ve created a swipe screen for mobiles from a YT tutorial. So right now I’m using only the left joystick and the entire screen to look around. It’s working but I’ve noticed something strange and I don’t know how to solve it. For example if I touch with one finger to look around and mistakenly I touch with another finger the screen, my character is turning around 180°.
How can I disable the second touch or something to avoid changing the view when already using the touch. Thank you!