UHHHG...I didn't like my play here. my opponent's flop bet scared the shit out of me, but I still think I needed to raise somewhere instead of just calling and then checking. Blah for weak plays! What's your line here?

Party Poker Pot-Limit Hold'em, $4 BB (9 handed)

UTG+1 ($299)
MP1 ($252)
MP2 ($562.35)
MP3 ($321.6)
CO ($263.7)
Hopy ($390)
SB ($214.6)
BB ($370)
UTG ($392)

Preflop: Hopy is Button with , . SB posts a blind of $2.
UTG calls $4, 1 fold, MP1 calls $4, MP2 calls $4, 2 folds, Hopy raises to $20, 2 folds, UTG folds, MP1 calls $16, MP2 folds.

Flop: ($54) , , (2 players)
MP1 bets $51.3, Hopy calls $51.30.

Turn: ($156.60) (2 players)
MP1 checks, Hopy checks.

River: ($156.60) (2 players)
MP1 checks, Hopy bets $80, MP1 calls $80.

Final Pot: $316.60