Singer James Arthur says he fears long-term damage after a vicious attack left him needing five staples in his head.
The former X Factor winner, 28, was drinking with friends in Redcar last summer when Christopher Revell ran towards him from behind, smashed a pint glass on the back of his head and punched him.
In an interview with The Sun's Dan Wootton, Arthur said the ordeal had left him with serious anxiety.
"The worst thing about the physical damage is that I worry about head trauma, even when I'm playing football, something like heading the ball, I worry about it," he said.
Explaining how he grew up in a rough area and spent time in foster care, he said: "I've always looked over my shoulder, especially in my home town.
"But I think more so now in public I'm scanning around."
Revell, 31, the ex-lover of a woman Arthur had a brief fling with, was handed a five-and-a-half-year prison sentence after admitting wounding with intent.
Arthur said he did not blame the woman, Gemma Iveson, but added the pair were no longer in touch.
The attack came just as he was beginning a new stage of his musical career after being dropped by Simon Cowell's Syco label.
The singer told Wootton that he had just reached a place where he was feeling emotionally and physically good when "it happened".
"But," he added, "it makes the fruits of everything so much better."
Arthur's latest song, Say You Won't Let Go, which reached number one in September, has now sold more than one million copies.