Barnes was shown a straight red in the first half for kicking out at Kieran Lee, and his manager has urged better discipline from the striker in future.
"I think you would normally probably say you're not happy with him," BBC Sport.
"Angry? It's difficult to say because I played football, I know when you're on the pitch you do things which sometimes you regret after but I was one of those players so I'm not going to say anything to Ashley Barnes - I hope it doesn't happen too much.
"He knows what he's done and I'm not going to kill him, you try to make sure he controls himself better the next time."
Brighton are now five points behind the Championship playoff spots.