Flopped the nuts, PUKE!!!!! on turn

Villain is 40/15/2.9 over 300 hands.

Party Poker No-Limit Hold'em, $1 BB (6 max, 5 handed) FTR converter on zerodivide.cx

SB ($75.65)
BB ($99)
UTG ($27.90)
MP ($102.70)
Hero ($103.70)

Preflop: Hero is Button with K[img]/images/graemlins/diamond.gif[/img], Q[img]/images/graemlins/diamond.gif[/img]. SB posts a blind of $0.50.
<font color="#666666">2 folds</font>, <font color="#CC3333">Hero raises to $4</font>, <font color="#666666">1 fold</font>, BB calls $3.

Flop: ($8.50) T[img]/images/graemlins/spade.gif[/img], 9[img]/images/graemlins/club.gif[/img], J[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
BB checks, <font color="#CC3333">Hero bets $5</font>, <font color="#CC3333">BB raises to $15</font>, <font color="#CC3333">Hero raises to $40</font>, BB calls $25.

Turn: ($88.50) J[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">BB bets $20</font>, Hero ???


I wanna smash something!! What do I do here, and on future streets? Can I really throw this away?

[PoBoy321]

I fold. I think that BB 4-bets the flop if he has KQ or 78. I think that JT, J9, TT and 99 are really the only hands in his hand range that wouldn't 4-bet the flop.