I said it before but I really think Lila needs to be an akuma's target.
The main reason why I say this is because I honestly believe that would be the best way for her to wake up and put a stop to her lies or, at least, move on from her grudge against Ladybug.
I've mentioned before Lila clearly thinks the worst thing that could happen is being exposed as a liar, hence, her hatred towards Ladybug. But in all fairness being targeted by an akuma is definitely a lot worse.
And this is what I came up with:
Since she had been telling everybody about her "amazing" life, there would obviously be a student who would've heard of her claims of knowing their idol. So this person-who I imagine as shy and introvert like Marc- would use all their courage to ask her if she could let them meet that celebrity or giving them something done by our little cinnamon roll and see what they think of them as artists.
Of course, Lila would be like, "Sure! I'm sure they love it!" because it'll mean she's gained more people's attention and adoration.
What she doesn't expect, though, is that they would often ask about it, "Lila, have you talked to them yet?", "Have they told you anything?", "Did you find a moment to ask them?". It's a given Lila would be pissed after being pestered so much about someone she doesn't care about at all, for the most part (especially if she's not alone) she'll answer "No, sorry. You know celebrities.. Always so busy!" But the moment she's sick of them she'll snap in her oh, so characteristic way, "You know, I have talked to them. They hate it. Sorry. Better luck next time!".
That was supposed to leave them devastated, which it kind of does, but they decide right after they'll keep trying until they've proved themselves worthy of their approval!
But when they go to tell Lila just that they see she's already gone, they ask the students who tell them she was headed to the park.
Since Lila has this tendency of truly snapping when she's alone, she would do just that, not realising her little "fan" is right there, "Gosh, they're so annoying! Always asking me about their stupid idol and their even more stupid opinion of their ridiculous job! I mean, even if I actually knew that mediocre star, they would never like such horrendous thing!"
That's when they feel at their worst, they've been fooled, just like they feared they would be if they ever opened up to anyone. While they're thinking it over, they remember that girl in Lila's class, Marinette, who's never been a fan of hers at all. She even mentioned the need of exposing her more than once! That's when they see red, Lila has probably been lying to everyone about everything and getting away with it. Someone must stop her.
Then Hawk Moth feels their anger and sends his akuma to infect them: "Honestigator, I am Hawk Moth. That girl's played with your feelings and shattered your dreams with her lies. I'll give you the power to show her and everyone in Paris how lying always comes with consequences. But in return you must bring me Ladybug and Chat Noir's miraculouses. "
So they make their deal and our little victim becomes "Honestigator" a supervillain whose powers allow them to make anyone tell the truth.
So Honestigator appears at wherever Lila is and she's surrounded by a lot of people. They will obviously give their bad guy speech: "Lila Rossi, you've been taking as for fools for way too long, and I'm the one who will put an end to it!" and throws her their "honesty sphere". Which makes her reveal everything she ever said were only lies to become the centre of attention.
**The main reason it goes that way and Lila gets exposed is because otherwise my little bean would be considered the liar and I love them too much already to give them such fate.
After seeing this, even if Marinette's somewhat pleased someone finally saw through Lila's façade, she still knows she's gotta take them down.
And you see, this is where things would get interesting because Honestigator would aim at LB & CN to make them confess their secret identities and where Master Fu's hiding.
After a rough battle they succeed at bringing them back to normal and Ladybug consoles them explaining they know how they feel but it's best to move on given Lila shouldn't be able to hurt them anymore after what happened.
And speaking of Lila, Ladybug would probably go after her to have an honest talk with her, much to the girl's displeasure.
"Lila, look. You don't have to forgive me for when I harshly exposed you and I don't expect you to do it. But listen, you really need to stop lying. This is the main reason why telling everybody we were friends and leading them into thinking something you're not is so dangerous. Getting called out isn't nearly as bad as being targeted by someone who only wants revenge. So, please, Lila. For everyone's sake, including your own: stop".
Of course Lila would still be mad at Ladybug, but as much as she hates to admit it, she does have a point just this once. So, even if she doesn't stop being who she is (change is a long process) she at least keeps her mouth shut about her "totally amazing" life.
Thank you so much for being with me through this.
I gotta admit, although my idea of Lila being a target has been around for a while, Honestigator's powers are based off Malediktator's and @lunian 's "La Justice" (ABSOLUTELY AMAZING JOB). Hope I didn't bother anyone, but it just fit. So. Well!! <3