I'm gonna guess her potion is actually an aphrodisiac that also temporarily lowers inhibitions.
The irony then is that all these girls have nursed secret crushes on her all along. She was popular, she just didn't know it.
I wonder what would happen if she drank the potion herself.
I think that it is a straight (no reverse pun intended) love potion of the "makes target fall in love with first person they see" type, but with an extreme short-term effect right after use. So it does make them fall in love with her, with the initial aphrodisiac/inhibition remover effect being a one-time deal.