Bodog 50$ fullring
hero is UTG with KK, villian is MP.
hero raises 4 blinds, UTG+1 calls, villian calls, everybody else folds.
flop is Q94 rainbow
hero pots it, UTG+1 folds, villian raises the amount hero bet, pot is now the same size as hero's stack, villian has hero covered.
what does hero do?