I can't believe that I missed such a big update from August! I missed this major development in the story. Σ(  ̄□ ̄||)
- Spoiler alert for those who haven't read past chapter 83 yet -
That aside, I do not believe that influence can cure the parasite shrub like Hanae said.
It could be possible that it slows down or temporary cure/improve the effects of the curse but the parasite shrub is still inside the body. Once the influence is transferred away, the curse will spread again. Sakae's influence mentioned that Aoi's body was not a safe host. After Aoi transferred Sakae's influence to a butterfly. I saw their hand turned back how it was before. That's why I don't believe it's the cure to the parasite shrub for now.
Hanae said he saw everything until the transfer of Sakae's influence to the butterfly. He may have forgotten Aoi's hand after the transfer when he woke up. After all it was a dream, it's possible to forget some details once you wake up.
However, I could be wrong. ( ̄∇ ̄")
Can't wait to see what will happen next.
I know I'm late with this and I usually don't care about these things.
However, I agree with Hanjoon.
Shiru and Sanghoo should just date already. Those two are so obvious. ╮( ̄▽ ̄")╭