Francesca,
One more person here who had tongue surgery, neck dissection and no radiation. Similarly to Ginny, I too wonder if I did enough, but this of course lessens as time goes on. I did see a radiation oncologist, who did not advise radiation after the results of my surgery showed clear margins and clear nodes.
What it comes down to is: if I get a recurrence, then I probably did the wrong thing, if I don't then I definitely did the right thing.
Jerry