The Montreal Canadiens scoring leader missed the final two games of the regular season and the first game of the post-season after he fell into the boards after a check during a game against the Panthers in Florida.
"I had very bad symptoms for two or three days," Pacioretty said Thursday. "But as soon as they went away I didn't feel anything significant.
"A lot of it came from my neck because there was a whiplash effect."
Pacioretty spent a few days in Florida with his parents after the injury. He said he felt dizziness and only went outside after dark. With concussions and possible brain damage a hit topic in professional sports in recent months, the injury raised concern for the married father of one's long term health and his family.
"I tried to get up the next day and I had a mini panic attack," he said. "I just wanted to go back to sleep.
"But once they relieved the neck tightness my head started to feel better."
He said he has felt no symptoms since he returned to the ice.
The 26-year-old took a few games to find his rhythm in the playoffs, but improved during in a 4-2 series win over Ottawa in the first round.