You've got to get obsessed and stay obsessed

I think her death is ambiguous in canon. It's likely that JK has said in interviews that she died from her wounds after the battle, but I think it's up to the reader's interpretation. When I think of Lavendar, I like to think she survived, but with scarring similar to Bill Weasley's. Fenrir Greyback was not transformed when he attacked her, so she'd have some contamination, but likely not become a werewolf, as happened with Bill.