Communication failure between lovers (even platonic or potential lovers) is a staple of Pixie Trix Comix, and this is a prime example. Teddi never bothered to ask exactly what had happened to Abby, and Chloe was incapable of giving anything resembling a coherent explanation. I expect that, now that Pandora has returned, the time will eventually come when she asks Abby to sit down with her and Teddi and tells her to detail the events that ended up turning her into a succubus. Then Abby will say:
1) That she herself injected Chloe's blood and Kimmy's ectoplasm into her circulation system (at night, when nobody was watching)
2) That the only result was transforming her into a child with horns, wings and tail
3) That two demon hunters tried to kill her but Chloe fought them to protect her (and almost died at their hands)
4) That Chloe was willing to sacrifice her breasts to turn her into a human again, but she refused to sign the contract
5) That Chloe's boss then offered to turn her into a grown-up succubus, and she immediately accepted (even though Chloe was yelling at her to refuse)
6) That she doesn't even know what she sold in exchange of her new body, tee hee!
And I guess this will be the beginning of a "Where's Chloe?" chapter, in which we will see a desperate, apologetic Teddi searching high and low for Chloe.
(Let's just hope he doesn't strangle Abby first.
)