I think it would’ve been about 2008 and I saw it on tv, a color film in English, but all I remember is a scene where a guy that was being held in prison started eating into his arm to remove something that had been surgically implanted there prior (by himself?) I think it was a necklace or something else with a long chain, and I remember it had a distinctly supernatural vibe, but I may have been misinterpreting it(?)
Check “A Beautiful Mind” (2001). The hero is looking for an implant that is not there. He is in a psychiatric clinic.