Balotelli, who has scored seven goals since his January move from Manchester City, also threw a tantrum at the end of the 2-2 draw against Fiorentina after he was involved in an altercation with rival goalkeeper Emiliano Viviano.
He stormed into the tunnel gesticulating angrily although it was not clear what had upset him.
Earlier, the 22-year-old Italian had been booked for failing to retreat at a free-kick and he will miss next week's Serie A match at home to Napoli, direct rivals in the race for a place in the Champions League, for accumulated yellow cards.
He was lucky not to be sent off for a late challenge on David Pizarro in the closing minutes.
Balotelli's problems began on Saturday as the team travelled by high-speed train to the game in Florence.
Having been mobbed by fans at Milan's Central station, Balotelli was then caught smoking in the toilet by a ticket collector.
Balotelli was ticked off by the train guard who told the club's chief executive Adriano Galliani: "You need to pull his ears. He was smoking in the bathroom," La Gazzetta dello Sport reported.
Smoking is banned on Italian trains. "I want to say that we're going to fine him," Galliani told the newspaper.
Nevertheless, Balotelli's weekend's misdemeanours paled in comparison to his antics at Manchester City which included rash tackles, arguments with manager Roberto Mancini and a bizarre incident where he set fire to his house after letting off fireworks in his bathroom.
His coach Massimiliano Allegri stood by the player.
"Balotelli took a lot of blows in the first half," he told reporters. "We can't expect him to be decisive every Sunday, it would be great if he could but it can't happen."
