JJ and can't figure out opponent

[Crumpled Ear]

Reno, Circus Circus, 3-6

I've been here an hour and main opponent has been in about a fourth of the hands but hasn't shown any of them down.

Preflop--I'm under the gun with JJ and raise. All fold except CO and BB who call.

Flop: Q /images/graemlins/spade.gif 9 /images/graemlins/diamond.gif 8 /images/graemlins/club.gif (3 players)
BB checks, I bet, CO raises, BB folds, I call.

Turn: (Q /images/graemlins/spade.gif 9 /images/graemlins/diamond.gif 8 /images/graemlins/club.gif) 2 /images/graemlins/heart.gif (2 players)
I check, CO checks.

River: (Q /images/graemlins/spade.gif 9 /images/graemlins/diamond.gif 8 /images/graemlins/club.gif 2 /images/graemlins/heart.gif ) 3 /images/graemlins/heart.gif (2 players)

I bet, CO raises (what the ...?) what should I do?

[Crumpled Ear]

CO has KQ offsuit for a pair of queens and takes it over my JJ. Dang!

[bernie]

Call. You could very well have the best hand. I sure wouldnt be sure enough to fold here.

b

[The Dude]

Did you consider check-calling on the river? I'm not necessarily saying it's right here, but if you always bet the river here after the turn is checked through, you're making a mistake.