100NL I Attempt to Bluff and then Magically Improve... Now What?

[74o_Clownsuit]

Villain is playing about 30/5/1.5 but only over a 70 hand sample size. I'm playing pretty aggressively, raising a ton in position and c-betting most flops. I decide to try a check-raise here to mix things up a bit. I don't recall Villain and I tangling too much or him doing anything totally out of line.

Full Tilt Poker, $0.50/$1 NL Hold'em Cash Game, 6 Players
LegoPoker Hand History Converter

BB: $221.15
UTG: $179.30
Hero (MP): $167.45
CO: $112.60
BTN: $90.85
SB: $11.75

Pre-Flop: J A dealt to Hero (MP)
UTG folds, <font color="red">Hero raises to $3.50</font>, CO folds, BTN calls $3.50, 2 folds

Flop: ($8.50) 8[img]/images/graemlins/spade.gif[/img] 4 8 (2 Players)
Hero checks, <font color="red">BTN bets $4</font>, <font color="red">Hero raises to $13</font>, BTN calls $9

Turn: ($34.50) A (2 Players)
Hero???