10/20 Stars - Bottom Set on Monotone Flop

[Mad Genius1]

Game is 5-handed. In UTG+1 Hero ($4200) picks up 77 and makes it $80, the standard PF raise thus far in this game. Next to act goes allin for $138, SB calls, BB calls, and I call the additional $58. BB is the villian in this hand with $3600. My read on him thus far is that he is very active, loose, fairly aggressive, and somewhat overplays his hands. Hero probably has a fairly loose-aggressive image but has not done anything out of the ordinary yet.

Pot is $550.

Flop Jd9d7d. SB checks, and BB bets $500 into dry sidepot. What's your plan for the rest of the hand?