My halacha teacher this year said ayin hara doesn’t happen unless you believe in it.
Then he showed us something cool to see if you have ayin hara or not.
He filled up a bowl with 6 spoons of water then you dip the tips of your 10 fingers in the water and put in on your face.
After that, count how many spoons are in the bowl. If there’s more than 6, you have ayin hara on you. 2 girls in the class tried it. 1 girl had less than 6 spoons and 1 girl had more. My sister tried it at home and had 9 spoons at the end!