He needs to exploit his space more. In Brazil he's very spoiled because he has tons of space
One would think that the Brazilians who are generally regarded as being better technically than the English and better at passing and possession would actually enjoy playing on the large Wembley pitch. That was really not the case. The better players actually enjoy playing on larger pitches because it gives them more space to work with. It was not like Brazil or Neymar were playing at Getafe. Wembley is actually one of the biggest pitches in Europe.
And with this being a friendly, England actually played more offensively and were a lot more adventurous than usual (since it was a game in which they could take risks), this was not the England that played like Chelsea of last year that was ultra-defensive like they were in the Euros. There was plenty of space for Brazil to exploit. It's not like Neymar was being man-marked or double teamed or they loaded up on his side of the pitch when he got the ball (like it happens with Ronaldo whenever he plays for Portugal). England did absolutely nothing out of the ordinary that would result in Neymar in having such a bad game. This was a thorougly inept performance, it was not like he was going up against great defenders either (Cahill or Johnson are not great defenders by any stretch of the imagination). There was not single moment that I remember in this match in which he did anything that could've provide a spark or moment which you could get excited about.
You'd think that playing against a team that was being more adventurous than usual and the larger pitch would actually give more opportunites for Brazil and Neymar to exploit but Oscar really looked like the only player out there was capable of producing anything of note and Lucas Moura when he came on actually livened things up a bit(he actually should've started). At this point in time, Oscar and Lucas actually look like better footballers than Neymar.
That doesn't mean that Neymar doesn't have any talent or skill but with the asking price and media attention + hype, he's really not worth it for Barca. He is by far the most overrated footballer in the world and that is not an exaggeration. There's nothing that i've seen of him either in this match or in previous ones that actually lead me to believe he's anywhere close to the asking price which he is reportedly worth.