Gibson posted a picture of himself at a friend's wedding via social media site Instagram on Sunday, showing his right eye bruised and closed over, and a cut below his eyebrow containing multiple stitches.
The 28-year-old posted another photo on Tuesday, saying he was having plastic surgery.
"He's had swelling above his eye drained," Evans said.
"It was drained by a facial specialist who is a plastic surgeon, but it is not plastic surgery."
Evans said there was no other damage to Gibson's face as a result of the head clash, and he would be available to take on North Melbourne in Hawthorn's final pre-season match in Craigieburn on Saturday.
Josh Gibson is a defender in AFL Fantasy. He averaged 65 points in 2012. Register your team at our AFL Fantasy hub