Cunha was sent off for assaulting Bournemouth defender Milos Kerkez, as he punched, kicked and headbutted the Hungarian.
The Brazil striker has scored Wolves' equaliser to take the game into extra-time.
He posted to social media: "In the end another game where you did your best. I couldn't lose my head at the end. Sorry."
Pundit Paul Merson described the incident: "Cunha's been sent off for a full house. He gets called offside, he goes to try and get the ball back off him.
"They're all round him, so he punches Kerkez, he goes down, kicks him, he gets up and then he headbutts him. Full house, whole lot.
"The ref goes and gives him a red card, he cannot believe it. A little kick and then he gets up and it's a headbutt. He's arguing with the third linesman as well."