Where's the cut? Depending on how deep it is, it'll leave a scar.

My best advice? Cauterize it. Ruin the Z to the point it's unrecognizable.

Cutting off your hand might work too, but Cauterizing it gives a chance that you keep the hand.

You know what's worse than Chinese water torture? Isolation.

Total complete isolation, locked away in a cell without any human contact. No natural light or external sound.

That or being stuck in that room that has no sound, the world's quietest room or whatever. So quiet you can hear your blood pumping in your ears.

It knocked?

Unless it has a sense of humour, I'm guessing it needs permission or an invitation to enter your room.

I considered maybe it's just a killer but the supernatural Alexa makes me feel its more likely something supernatural.

I thought the rule would be if something felt off, always trust your instinct. Especially if all the enemy needs is an "invitation"

You could've tried this, ask them to try to enter without permission. Then, observe their reaction.

Tell them you won't harm them for trying, it's just that you're not giving explicit permission to enter