I'm not entirely sure which specific 'Creepypasta kid with mono' story you mean. There are many Creepypasta tales out there. It could be about a kid who has mono (infectious mononucleosis) and then something very strange or terrifying starts to happen to them, like seeing strange apparitions or experiencing abnormal events. But without more details, it's hard to tell the full story.
The 'Creepypasta kid with mono' story might involve a child who contracts mono and while being sick, starts to notice odd things in their surroundings. Maybe they're isolated in their room due to the illness, and as they're in that weakened state, they begin to sense a malevolent presence. It could be that the mono has somehow made them more sensitive to the supernatural, or it could be that there's a more earthly, but still creepy, explanation like a stalker or something lurking outside their window. However, this is just speculation as the exact story details are not clear.
Well, in a possible 'Creepypasta kid with mono' story, the kid with mono could be the center of a very disturbing sequence of events. Since mono often makes a person feel weak and fatigued, this state might be exploited in the Creepypasta. For example, the kid might start having vivid nightmares that seem to spill over into their waking life. They could see a figure in their room that they initially think is a hallucination caused by their illness, but then the figure starts to interact with their environment. Maybe things in the room start to move on their own, or they hear strange whispers. This could all be building up to a big reveal or a really terrifying climax that makes the story so 'Creepypasta' - ish.
Chapter 910, "This place isn’t fun, I want to go home!", is the clearest early answer because it turns Jiang Bufan's situation into a concrete plot event. It opens with Jiang Bufan was not very shy. and closes on It's all sister's fault for bringing us here..
Chapter 753, "Final Judgment", is the clearest early answer because it turns Fang Wenzhe's situation into a concrete plot event.
Chapter 721, "Apology", is the clearest early answer because it turns Jiang Cheng's situation into a concrete plot event. It opens with Jiang Li's car had just passed a traffic light when a phone call... and closes on Jiang Li's words continued— "If I'm not wrong about your facial....
Chapter 706, "How Did a Good Person Turn Out Like This?", is the clearest early answer because it turns President Sun's situation into a concrete plot event. A useful checkpoint is the way the scene starts with Inside the building, President Sun and his group watched Zhao Lang...
Chapter 851, "Peace Charm", is the clearest early answer because it turns Jiang Li's situation into a concrete plot event. A useful checkpoint is the way the scene starts with She initially came with the expectation of becoming the Gu Family's...
Chapter 703, "Slap Oneself", is the clearest early answer because it turns Miss Jiang's situation into a concrete plot event. Early on, Wu Daoshan quietly raised his head to size up Zhao Lang, and sure.... By the end, Young Master Gu was intending to back Jiang Li..
The best chapter pointer here is Chapter 3, "Madam, the eldest young master has been missing for over half a month". It opens with Qiao was still annoyed at the attitude of this unknown girl when she heard... and closes on Jiang Yan, forced into a marriage with someone he did not love, had....
Chapter 13 is the strongest chapter-level answer because it starts from Sensing that something was off with Jiang Yan, Jiang Yan dismissed the... and follows through on How could this happen..." Lin Manru didn't want to hear any more of her....
The best chapter pointer here is Chapter 9, "The Qiao Family's business isn't big, but they have quite the audacity". It opens with Exactly, the Qiao Family isn't that great either. and closes on Qiao, unable to save face, slapped her daughter across the face, "Didn't I....
The best chapter pointer here is Chapter 25, "He's Actually Mr. Shen's Son?!". It opens with Therefore, from his childhood, Jiang Shixu had felt an extreme aversion to... and closes on Having worked beside Shen Lan for over a decade, she had been there when....