Ænigma (1988)
By chance, this movie also opens with a student trying to bang but getting pranked by their friends and ending up in a hospital. Instead of a nice wholesome Canadian slasher tho, this movie is a batshit Italian movie from Lucio Fulci. It's also pretty bad, and fairly restrained by Fulci's standards of gore.
It begins with ugly duckling Kathy getting dolled up for a date with her fitness instructor. He drives her to a secluded area to engage in some heavy petting, but as soon as things start getting hot, all her "friends" show up and start honking their horns and laughing at her, causing her to run away into a busy street and get hit by a car. She's declared brain dead at the hospital and placed on a respirator. She begins having an out-of-body experience, as her soul/spirit/whatever hovers over the bed. Some time passes, and new girl Eva enrolls at school. She's recovering from a mental breakdown, but she says she's all better now and ready to screw a lot of guys ("Let me put it this way: anything in pants.") She starts off with Mr. Vernon, the horny fitness instructor from the intro, but he suddenly comes down with an unexpected case of DEAD.
It turns out that Kathy's spirit has inhabited Eva's body, and she's taking revenge on perpetrators of the prank, using BLACK MAGIC. How does Kathy know black magic? Look, she's from Louisiana, okay? I hope that's enough explanation for you because that's all you're gonna get. Her mother is a distinguished mentally-challenged fellow and there's a bit of a plot thread that's briefly mentioned once and never again that her and some of the teachers may be involved in some kind of cult activity, and I think they're supposed to be hinting that maybe Kathy's father is the devil, but it's never expounded on beyond a throw-away line. At any rate, Eva/Kathy continues to befriend Kathy's tormentors and then off them with magical means. One girl gets crushed by a statue that comes to life, one girl throws herself out of a window after being shown visions of her boyfriend's decapitated corpse, some girl gets murdered by snails. Yes, murdered by snails.
The movie ends with a second revenge subplot, where Eva/Kathy gets sent home for being too crazy and she gets super obsessed with her neurologist (who she was banging). She breaks out of her house and runs back to the hospital to find him now banging her roommate. She tries to stab both of them, but Kathy's mom shows up and unplugs Kathy's respirator, sending her spirit to the shadow realm once and for all and causing Eva to collapse to the floor while the credits roll and some godawful pop song called Head Over Meels(sic) plays. This movie was absurd, it was terrible, but I did have a few good chuckles at how stupid it was.