The key to curing the Overgrowth, as always, relies on emotional honesty. If it has to do with admitting something that your character has denied to themselves, admitting it to others would likely have the desired effect, regardless of whether or not the other character already knows it, because the key would then be admitting it to yourself

It doesn't matter who they're confessing to; it can be the same person as last time, or it can be someone new, as long as they're not merely repeating the same confessions they did the last time - you've already unburdened yourself of those secrets and lies, after all!