JJ meets aggression on low flop

villain was a pretty solid player from what i saw after about 50 hands... what to do? what could i have done differently? thanks in advance

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

saw flop|<font color="#C00000">saw showdown</font>

UTG ($53.30)
MP ($131.76)
CO ($52.68)
Hero ($121.05)
SB ($72.42)
BB ($129.75)

Preflop: Hero is Button with J[img]/images/graemlins/club.gif[/img], J[img]/images/graemlins/diamond.gif[/img]. SB posts a blind of $0.50.
<font color="#666666">3 folds</font>, <font color="#CC3333">Hero raises to $3</font>, SB (poster) calls $2.50, BB calls $2.

Flop: ($9) 5[img]/images/graemlins/spade.gif[/img], 7[img]/images/graemlins/spade.gif[/img], 2[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(3 players)</font>
SB checks, BB checks, <font color="#CC3333">Hero bets $4</font>, SB calls $4, <font color="#CC3333">BB raises to $15</font>, Hero...