My remote stop working after it was dropped in water. Is there a process to dry and power it back up

The Apple TV remote is not advertised as either water resistant or waster proof so there is no guarantee it can be revived at all. As with any electronic device water is the enemy. Your best bet is to set it aside and let it dry out for at least several days, maybe more. If your remote is the older type with a removable battery then remove it too. If it’s newer and has a sealed rechargeable battery then there’s nothing else you can do except hope. A replacement remote can be purchased from Apple at this link.

Siri Remote - Apple