QQ overpair being played back at what to do?

[squidladder]

Villain
27/10/4


Full Tilt Poker
No Limit Holdem Ring game
Blinds: $0.10/$0.25
6 players
Converter

Stack sizes:
Hero: $23.35
UTG+1: $25.90
CO: $5.70
Button: $28.80
SB: $36.95
BB: $24.15

Pre-flop: (6 players) Hero is UTG with Q[img]/images/graemlins/spade.gif[/img] Q[img]/images/graemlins/heart.gif[/img]
<font color="#cc0000">Hero raises to $1</font>, 2 folds, Button calls, 2 folds.

Flop: 4[img]/images/graemlins/diamond.gif[/img] 2[img]/images/graemlins/diamond.gif[/img] 6[img]/images/graemlins/club.gif[/img] ($2.35, 2 players)
<font color="#cc0000">Hero bets $2</font>, <font color="#cc0000">Button raises to $4</font>, hero?