Unless ONE of you now goes "all in" (and the other accepts), there is no reason for either of you to turn your cards face up. Besides the "all in" player, you are still in competition with a second opponent whose moves are not predetermined. As such, you and the second opponent do not turn your cards face up.
Though, what is Fourth Street in poker?
In flop games, it is the fourth community card dealt (also known as "the turn") and represents the third round of betting. In Stud games, it is the fourth card dealt to each player and represents the second round of betting.
So anyway, do you have to call your hand in poker? Casinos in the US generally have the "cards speak" rule. That is, when a hand is properly tabled--exposed to everyone at showdown--it is the responsibility of all players, the dealer, floormen, and anyone else present to see that the pot is awarded to the best hand shown, regardless of what the players might say.
Despite that, who can raise in poker?
If there are three players in the hand and Player A opens, player B can raise that bet. At this point Player C or Player A can choose to re-raise when the betting action gets back on them. When faced with a re-raise, players have the options to call, fold or re-raise again.
Can you raise after a call?
Any player facing a bet at any stage of the hand can fold, call, raise, or go all in.