كتب : وكالات
The 18-year-old sparked a brawl in Santos' 2-1 defeat by Ceara last Sunday after rebuking an opponent for his rough marking.
He also verbally assaulted Santos coach Dorival Junior and captain Edu Dracena after they refused to let him take a penalty in Wednesday's 4-2 home victory over Atletico Goianiense.
"I'm here to say more than sorry and (I expect) no pardon. I got home and saw what I'd done," Neymar told reporters.
"I acted wrongly, I left even my father and mother shocked ... I'm ashamed of what happened.
"I say sorry to Dorival, sorry to Edu, who is the team captain, and to my team mates. I apologize to ... kids who look up to Neymar. Forgive me for what I did."
Neymar turned down a 20 million euro move to English side Chelsea and signed a new five-year contract with Santos last month.
He scored on his Brazil debut in their 2-0 friendly victory over the United States in August.