The Pain Inhibitor is a cybernetic implant granted to Conrad Kellogg by The Institute. Though its purpose is never stated in-game, it can be implied by its name that it dulls painful stimuli, allowing Kellogg to fight more effectively without distraction.
It can only be found on Kellogg's corpse after killing him, and cannot be pickpocketed. Also, unlike the cybernetic implants found in previous games, the player cannot have it implanted in themselves, and thus its only purpose is to provide story flavor. It can also be sold, or placed as decoration.
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