he was stung in the belly, but it wouldn't have been too big.
the scar on his shoulder is from the witch king
the one on his chest is from the cave troll in moria, yes he had on the mithril coat but that hit would have still incured a sizable bruise or even a cut. The coat saved his life but did not leave him unscaved.
and the bruises around his neck is from the ring, remember it gets heavier and does weigh him down
I thought in the movie Shelob got Frodo somewhere on his chest instead of on the back of his neck where it's supposed to be.
I noticed the bruises on his neck and I figured it had to do with the ring but I couldn't figure out just what it was. It's kind of scary that the little chain gave him those bruises though.
i cant remember who posted about Frodo's finger being there at the grey havens but you never see his left index finder during that scene you only see his right. (more clever camera work). i thought the same when i first watched that scene but as i've seen the film for the fourth time now, i am pretty sure you never see his left hand during the grey havens.
The markings on Frodo. The marks around his neck are visual marks from the chain and the ring to emphasize the weight and burden. One of the body wounds is from Weathertop and the other is either from Moria and is a bruise or (though it doesn't make sense) from when Shelob stung frodo.