This is the kind of story that would really only work as a series instead of a oneshot. As it is, it just feels terribly rushed having to cram what should have been an entire redemption arc, just so it can be "neatly" resolved at the end but it just falls flat.
Some readers, including myself are left with an unsatisfying feeling of not enough comeuppance delivered, considering how long the bullying and abuse has been going, and it's just way too quick of a friendship forming between a former abuser and her victim. Not very credible given the pacing.
The excuse given to trigger the bullying also felt weak: stress from getting stalked? That doesn't entitle her to hurt anyone (except the stalker), so she's still a shitty person. There's also a pinch of victim blaming to the mix: "she felt like an easy target" and that does not help her win any sympathy for me. This was too easy given what she inflicted on the other girl.
Minus the body swapping, similar bullying plots have been done better in
Onani Master Kurosawa and
Takopii no Genzai because there's room to better flesh things out. A weird choice to cram this kind of plot in a oneshot.