It was always going to be an emotional fixture for Neymar, and going in to the match he must have known or been told that he'd need to control his emotions.
It was a truly horrible match for him, and I'm certain he felt victimised due to the 'special treatment' he receive and referees handling of him. The cynical Colombia players knew exactly what buttons to press. However, despite all the negatives surrounding the match, it could turn out to be an important learning curve in his career.
Out of the comfort zone of the Barcelona environment, without his confidant and mentor Messi to guide me and advise him, he is more susceptible to losing his head. At Barca he has a group of grounded individuals that have achieved everything in the game, that will keep his feet on the ground.When he's with the NT, he doesn't have this so much.
For Brazil, he is the 'Captain', 'The Golden Boy', 'The Saviour of Brazilian Football', he is treated like a demi-god. Neymar isn't ready to take on all that responsibility yet... as shown yesterday.
The Captaincy looks like just another burden that Neymar doesn't need right now.