I have been confused over tomato skins and liver flukes too, and spent months agonising over whether the red rolled up skins I was passing were tomato skins or flukes.
This is what I have learnt thru trial and error....sometimes some really silly trials to test whether the skins were tomatos or flukes...
1)There is no doubt that tomato skins are undigestible and will pass through you intact.
I confused these for flukes. In the end I took them to my Naturapath and we muscle tested them on me....and my body liked them!! This rather confirmed that they were tomato skins.
2) The Hospital of tropical diseases performed Elisa tests on me for Flukes and blood flukes and it came back negative, as a double confirmation.
However, as I potentially did not have liver flukes and therefore have never seen one, I cannot possible judge whether liver fluke remains do indeed look like tomato skins!!!
The only thing I can reccomend is you lay off eating fresh tomatos for 3-4 days and see if you are still passing red rolled up bits...