How did lusamine survive after being freed from Nihilego?

Question

From a different thread, it said lusamine was poisoned in order to be fused with nihilego. And.. They were fused for quite a bit, so how did lusamine exactly survive that and not like.. You know, die?

This might be a dumb question but I'd like an answer nonetheless.

Comments

"When Nihilego latches on to a host's head, it does not manipulate its actions directly. Instead it awakens the host's own capabilities and boosts them to an extreme extent in order to protect itself. It injects the host with a sort of neurotoxin to achieve this effect. This neurotoxin of Nihilego's is incredibly stimulating and inspires feelings of extreme excitement and a lack of inhibition in its host."
https://bulbapedia.bulbagarden.net/wiki/Nihilego_(Pok%C3%A9mon)#Biology

Not every poison is lethal, especially in Nihilego's case.