I've not seen enough of Neymar to really comment but believe Slavo when he says he's generally fitted in really well at Barca.
He was massively hyped and put under enormous pressure from the get-go. Add to that his move from pretty poor beginnings into the bracket of the super-rich (and all the temptations that has to bring) and from what I can tell he's dealt with it all pretty well. I dread to think how I'd have behaved in similar circumstances.
Look at how some young prodigies under similar pressures have turned out.
Paul Gascoigne.
From this ...
to this
And this poor fucker obviously needs no introduction
Safe to say Neymar's doing fine
(And if the Laphroaig doesn't send you into a pleasant sleep then I'm not sure anything will)