Jack McCollough's reps have revealed that the head-butt, allegedly given by actor Kiefer Sutherland, left the fashion designer with a broken nose, which even had to be operated upon.
The reps for McCollough have said that the designer required surgery for his injuries after the alleged incident.
"Mr. McCollough suffered a broken nose in three places as a result of the assault. He received medical treatment last night after consulting with physicians," The New York Daily News quoted the rep as telling People magazine.
Although it was initially reported that the designer suffered only scratches on his nose, a source close to McCollough has now said that he "had to have his nose reset."
The source also said that McCollough was irritated that the ordeal had delayed work on his upcoming collection, and he "has no time to deal with this."
Sutherland's friends said that he whacked the designer at the Metropolitan Museum of Art's Costume Institute Gala in New York to defend the honour of actress Brooke Shields.
McCollough's camp called it "a vicious, violent, unprovoked assault."
The actor surrendered about 72 hours after the incident, which left the designer with a gash on the bridge of his nose.
Sutherland is due in court on June 22.