TT overpair faces turn action -- easy decision?

[jtr]

Party Poker 2/4 Hold'em (9 handed)

Preflop: Hero is MP2 with T[img]/images/graemlins/spade.gif[/img], T[img]/images/graemlins/heart.gif[/img].
<font color="666666">3 folds</font>, <font color="CC3333">Hero raises</font>, MP3 calls, Button calls, <font color="666666">2 folds</font>.

Flop: (7.50 SB) 8[img]/images/graemlins/club.gif[/img], 6[img]/images/graemlins/heart.gif[/img], 9[img]/images/graemlins/heart.gif[/img] <font color="blue">(4 players)</font>
<font color="CC3333">Hero bets</font>, <font color="CC3333">MP3 raises</font>, Button calls, <font color="CC3333">Hero 3-bets</font>, <font color="CC3333">MP3 caps</font>, Button calls, Hero calls.

Turn: (9.75 BB) 8[img]/images/graemlins/heart.gif[/img] <font color="blue">(4 players)</font>
Hero checks, <font color="CC3333">MP3 bets</font>, <font color="CC3333">Button raises</font>, Hero???

So what would you do? My overpair plus gutshot draw now faces a paired board and a possible flush, but may well still be good.

Pokertracker gave me a decent read on MP3 as loose-passive before the flop with surprising aggression afterwards. (Although I am ashamed to say I didn't check my notes fast enough to take this into account.) No reads on button as he had only just sat down.