At what point do they show Frodo with a scar from the cave troll.
The mithril shirt protected him if he had been wounded he wouldn't have said "I'm alright, I'm not hurt" would he, everything that happens after the cave troll stabs Frodo, leads us to believe that Frodo was uninjured by the troll.
Besides its fairly obvious which is the scar from the Wiki and the other is too fresh to be from the cave troll look at it, that is a very recent injury, not a scar.
Oh my gosh............I know this thread is old but Orlineelijahsgrl you are ridiculous. Sorry but in the fellowship, Frodo isn't scared but the cave troll only bruised! Aragorn heals him! Then when Shelob stings him he is jabbed in the neck not the back. Then when you see him in the tower the scars are from the blade he is jabbed with in the fellowship by the nazgul. And the other scar is from the ring!