Cards you encounter forget everything about the encounter at the end of the encounter, and cards you play forget everything about being played as soon as they are no longer being played. So if you have an item that you freely reveal to reduce damage suffered before acting, you can freely reveal that item again while acting and after acting if you need to. A monster isn’t affected by anything that happened to it in a previous encounter. Even though you’ve played a card to explore again, after that exploration you can play another. You have a memory, though, and it doesn’t cut you any slack. If you play a Dagger by freely shuffling it into your deck then draw one of two Daggers that are in your deck, you can’t rule out that it’s the same Dagger, so you can’t play it again on that check.