The Scream star was recently forced to deny rumors he had had cosmetic surgery after he was spotted sporting a black eye.
At the time, he declined to comment further on the operation - but now Arquette reveals doctors had to remove an osteoma, a bone tumor.
The treatment has left Arquette unable to move his right eyebrow.
Going public with his health crisis for the first time, the actor told U.S. talk show host Ellen DeGeneres, "I had an osteoma, I think it's called, so they took it out. I can't move my eyebrow yet.
"Its getting better, much better, but most of my friends are like, 'You used to move your eyebrows too much anyway.' No more James Dean cool guy stuff."
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