Live Poker: Nl600 - Going broke with Turned Set?

[DeusDeorum]

Blinds 1/3 - 9 handed

Hero is CO (550) and gets dealed 4:spade: 4:diamond:
Villain is MP3 (1000.-)

Sb posts blind, BB posts blind
UTG limps, call,fold,call,fold,call,call,SB raises 18.-, fold,call,call,fold,call,call

Flop
7:spade: 6
check around

Turn

check,check,check, Hero bets 75.- , fold, fold,foldMp3 raises AI

Was macht Hero?