I'm not your boss. You can play however you'd like. But I think you made some serious mistakes. I think in your heart you know this. I also think the game itself is still at risk. I think you know this, too. I think you also know that "talking to them" wasn't some magical ritual that fixed everything.

First, this is exactly why I don't allow any PvP in my game. Secondly, this is exactly why I don't allow anyone to do anything based solely on "it's what my character would do."

Because the obvious next step is "the rogue gets his revenge" and questions about whether its "fair" are going to be answered by the dice and a Rogue's Dex is going to be better than a Paladin's Wis and that sucks. You're going to be tempted to start fudging then to save the Paladin and that does make you a jerk.

If "it's what my character would do" works for the person who hit first, then it should work for the person who hits back. It's not out of bounds to say "explain to me why the rest of the group would keep protecting someone who acts this way."

You shouldn't have put the Hand of Vecna into the game. You shouldn't have done anything that lead to the Rogue to believe that the hand was "meant" for them, and that means however "cool" it felt to play the hand seducting the rogue you were sending mixed signals by neglecting that you also have to be the DM communicating the game state to the players, too. You have to learn to do both. But, there was nothing stopping you from saying "despite appearances, this wasn't actually meant to pay off your story. If you use the hand, I'll have to run _______ myself as an NPC until he's free of it" and then let them do the whole "what if I helped you fight it off" thing. We're DMs, making sure there's no confusion about what's going on is ultimately our jobs.

As a DM I have been exactly here before. And its time to eat a big plate of crow. Talk to the players again and this time apologize to both of them: you set them up to fail, you pitted them against each other, and you need their help to fix it. Since it's probably too late to just retcon it, you need them to help you figure out what to do to get the story back on track and everybody on the same team. That's also going to be a great time to introduce new "never again" rules about PvP.

You can get that crow down; it might not even taste that bad. Believe me, I beefed it harder than this and what came of it was stronger friendships and a better game. But it all grew out of me going "I never should have put you there. That's on me."

You can do this. This can be a huge opportunity to change how things have gone for the better. But it has to be a real rebuilding, not just a band-aid. Good luck.