Her shocked expression is more in the line of "How do they know I have a mole on my chest?" when she didn't sleep with any of them, rather than how she's been "exposed" of whatever she was accused of doing.
A classic red herring I'm afraid, so if someone jumped the gun and started blasting the girl with insults in the comment then idk man, maybe you're being too hasty.
My guess is that someone else is sucking those men, using a spider like how it's hinted in earlier chapters, and the spider's venom has hallucination effect on them.