Joe Mixon has apologized to the woman he brutalized in 2014 -- saying, "It's never okay to retaliate and hit a woman the way I did."
"I apologize. I regret what happened. And I'm sorry."
Mixon held a news conference in Oklahoma -- and got emotional as he apologized to the victim, his teammates and his family.
Mixon said he let his mother down ... "I disappointed her."
Mixon says he's still haunted by the incident and says he thinks about it everyday. He would have done things much differently and wouldn't have put himself in that situation in the first place.