Hanahaki is a fictional disease in which unrequited love causes the affected one to have flowers grow in their lungs.
The only cures known are to
A.Have the flowers surgically removed, once removed the affected one can never feel love for the person who caused their hanahaki in the first place.
or
B. Hope that their love will be requited once a confession has been made.

If the affected one doesn't get the flowers removed or get their love requited, the flowers will slowly kill them
#AceAlex