Bookworm having tried to counter-attack to make up for his earlier panic gets hit by the flaming cross. They probably should have taken the time to try and shut off the telepathic connection. As the moment they were hit by the flaming cross they would wail, terribly in extreme pain. The bugs they were sending toward the paladin's way never full received their command and would likely be incinerated by the flaming cross itself.

The telepathic connection and actual sound escaping from Bookworm would be nothing sort of an ungodly and pained screech as their carapace and body burned with extreme intensity. They clung to their cloak just screaming in absolute dread agony which was split among their normal managed talk way. They were doing their very best to simply not drop to their knees at the moment. Bookworm struggled to stay standing and aiming to pat out the fires. 

In a brief moment of psychic backlash the screaming, pain and horrible ungodly sounds of some unknown nature and creature would target right into the paladin's brain. It would feel like three sharp swords aiming to stab directly into his mind among the painful and agonizing wails and there was very little way to avoid all the psychic pain from it (unless the target was deaf). One could will themselves to resist, if they were focused enough but even then it was extremely likely that at least half of that sharp pain would flash into the mind. The very pain would aim to drive the paladin to move far away from Book-worm should they not be able to will through the portion of the pain that could be avoided.