WARNING: The following contains spoilers for Boruto: Naruto Next Generations Chapter 68, “Scar,” by Masashi Kishimoto, Mikio Ikemoto, Mari Morimoto and Snir Aharon, now available in English from Viz Media.
In the Boruto manga, Naruto's son has struggled with Momoshiki trying to take over his body. The Ōtsutsuki alien, however, gave up the opportunity to use the boy as a full-blown vessel after Kawaki harnessed his new Karma mark and mortally wounded Boruto to destroy the villain. It caused Momoshiki to download his DNA into Boruto prematurely before the takeover process could be completed naturally, which meant that while Momoshiki could never own the human's frame, his soul would still remain inside -- akin to how Kurama was stored in the Hokage.
Now, come Chapter 68, Boruto found himself back in Konoha after the battle with Code, keeping Momoshiki at bay. The scientists were left worried about what the future could hold, though, knowing an Ōtsutsuki inside such a powerful kid could only spell trouble. Unfortunately, when a solution was put forward, he rebuked it, opting for a deadly gamble.
In the med bay, Amado, Katasuke and co. were in shock over how Momoshiki repaired and resurrected Boruto. They're glad he blew his shot at downloading his mind into the kid, but were still worried over Boruto being fully Ōtsutsuki in terms of his body and ultimately, his power.
The team was adamant on having Boruto use the pills he took over the last few weeks to suppress Momoshiki, but in a head-turning move, Boruto shut that down. He said he felt something change in him due to Momoshiki's actions and now thinks he can control the monster inside. The scientists reluctantly trusted the teen -- but this wasn't wise at all.
It's not like Kurama and Naruto, who began to understand each other as loners, deciding to share power and become siblings. They looked after each other, but Momoshiki is still a villain who craves power by feeding on the world using the God Tree. Thus, because the Ōtsutsuki science is unpredictable and something Konoha hasn't unlocked, there's a chance he could find a way to take the body again in the future.
They admitted they have no clue when his soul will pop back up and attempt to corrupt Boruto too, so this invisible influence alone can cause Boruto problems in the field. It might mess with his powers, causing him to harm villains -- or worse yet, innocents -- if he's turned into a weapon of mass destruction that glitches.
Momoshiki would be pressing harder for possession, or at least to sabotage Boruto more than ever, so it's not smart to believe an alien so bitter wouldn't do something under the surface to make Boruto pay. Sure, he'd want the kid alive so his soul has a home, but that doesn't mean he can't cause the boy pain by harming the outside world.
Hopefully, Amado's crew can improve the pills or come up with a new treatment soon, but apart from the physical issues, someone -- maybe the concerned Naruto or Sasuke -- will have to chat with Boruto about the mental risk he's taking with an enemy who's been nothing but conniving and merciless in his war on the Hidden Leaf.