Keep hammering? Should I raise more on the flop?

Party Poker No-Limit Hold'em, $ BB (8 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

saw flop|saw showdown

BB ($54.10)
UTG ($116.85)
Hero ($105.55)
MP1 ($61.51)
MP2 ($102.20)
CO ($111.73)
Button ($75.35)
SB ($98)

Preflop: Hero is UTG+1 with 7, A. SB posts a blind of $0.50.
1 fold, Hero calls $1, MP1 raises to $4, 2 folds, Button calls $4, SB (poster) calls $3.50, 1 fold, Hero calls $3.

Flop: ($17) 7, 7, 8 (4 players)
SB checks, Hero checks, MP1 bets $10, Button folds, SB calls $10, Hero raises to $30, MP1 calls $20, SB calls $20.

Turn: ($107) 5 (3 players)
SB checks, Hero ???