Sounds like this one http://www.mangago.zone/read-manga/moonlight_garden_kang_unnie/
Sorry not that one. Forgot to put that it was transmigration. Thanks for helping tho.
Is it this??? Sounds very similar except for the turning into a flower part
http://www.mangago.zone/read-manga/when_the_villainess_loves/
Oh thank you!
I forgot that her disease makes her puke blood and that once she is buried a blue flower grow from the spot she is buried. But anyway. Thank you shinz!
All I remember is that the FL does not have long to live [up to a year at most, I think] because she has a disease that turns her corpse to a blue flower. I remember the female lead replace the original one because the original [who is a villainess]. FL love the original villainess as a hardcore fan.