pair of 8's Jack kicker. too aggy?

[AsusTek]

Party Poker 0.50/1 Hold'em (9 handed)

Preflop: Hero is SB with 8[img]/images/graemlins/heart.gif[/img], J[img]/images/graemlins/club.gif[/img].
UTG folds, UTG+1 folds, MP1 calls, MP2 calls, MP3 folds, CO calls, Button calls, Hero completes, BB checks.

Flop: (6 SB) 2[img]/images/graemlins/heart.gif[/img], 8[img]/images/graemlins/spade.gif[/img], 5[img]/images/graemlins/spade.gif[/img] <font color="blue">(6 players)</font>
<font color="CC3333">Hero bets</font>, BB calls, MP1 calls, <font color="CC3333">MP2 raises</font>, CO folds, Button calls, <font color="CC3333">Hero 3-bets</font>, BB calls, MP1 folds, <font color="CC3333">MP2 caps</font>, Button calls, Hero calls, BB calls.

Turn: (11.50 BB) 5[img]/images/graemlins/heart.gif[/img] <font color="blue">(4 players)</font>
<font color="CC3333">Hero bets</font>, BB calls, <font color="CC3333">MP2 raises</font>, Button calls, Hero calls, BB calls.

River: (19.50 BB) K[img]/images/graemlins/diamond.gif[/img] <font color="blue">(4 players)</font>
Hero checks, BB checks, <font color="CC3333">MP2 bets</font>, Button calls, Hero calls, BB calls.

Final Pot: 23.50 BB

Should I have open-raised the turn? I'm feeling uneasy about how I played this hand.