Cancerous Salmon Sashimi

Raw text (tldr version):

Pop out flowers salmon poison strip accidental in mouth back in time correct, but still aftertaste. Professor says imposs to correct because of Heisenberg/Schrodinger riddle/questions involving schrodinger cat. students say it will correct but professor is right. another girl dies I start throwing up, sort of feel it is dream but not sure

With details ("I like reading Max's dreams" version):

At an expensive restaurant, I am served an exquisite salmon sashimi dish. When I open the lid, a pop-out book mechanism causes some small flowers to pop out. Beneath the flowers lies the prized fish. The cook explains that each strip of sashimi is covered with a strip of poison; as long as you remove the strip and do not put the strip in your mouth, the food is completely safe.

Well lo and behold somehow I find myself chewing on this poisonous strip that I had just removed from my fish. "How did that get in my mouth?" I wonder. Incidentally, a generic girl beside me had suffered a similar fate; she too accidentally put the poison strip in her mouth. Anyway, it is too late. I am going to die from the cancer that this poison gives me. Ah, but maybe I can go back in time to remedy the problem by NOT eating the poisonous strip.

I ask my quantum physics professor (not a real person in real life): "If I go back in time and avoid eating the poison, will that fix everything?" The professor answers in the negative. I am greatly confused by this, since common sense would say that going back in time and avoiding the poison WOULD fix the problem. I ask some of the professor's students this very same question and they answer, "Yes, of course it would work." So I go back to the professor and he proceeds to explain exactly why it wouldn't work. It is a very complex explanation involving several case studies of experiments by Heisenberg and Schrodinger's cat. One such research article was titled something like "Heisenberg, Schrodinger, and a cat." The results of these experiments imply that going back in time to change something will have no effect on the resulting state of the universe; despite how hard you try, even if you blow up a building, in 5 minutes everything will have returned to normal. It is all very confusing to me but gradually I begin to be convinced that the professor is correct, even though I do not understand the proof at all.

So I try it. I go back in time. I carefully avoid eating the poison. I even avoid eating the fish entirely. Yet, just as the professor had predicted, 5 minutes later I can feel that all-too-familiar bitter aftertaste of the cancerous poison in my mouth, despite that I had not ingested anything! I realize that the quantum physics professor knew what he was talking about, and there is no way to remedy my situation.

A few days later I learn that the girl who also ate the poison strip had died. Her exposure was far more severe, because she chewed on it longer than I did whereas I spit it out almost immediately, so she died first. Nonetheless, I knew my end would come eventually. Already, I was feeling sick. Moments later I threw up. Some generic people beside me (only my sister is recognizable) tried to comfort me. I tasted the vomit carefully, trying to decide whether or not all of this was a dream. The feeling of vomiting and the taste/texture of vomit both felt quite real. I felt a bit dreamy but that could have been explained by an altered state of mind brought about by the sickness. I could not make a decision on whether or not I was dreaming, until I woke up.