Nope, Dyvath Fyr says that the corprus cure he developed worked only on you. It killed all the other patients.
Otherwise there would have been a major medical discovery.
And really, your actions conforming exactly to prophecy, with the mutually antagonist and incredibly learned deities of Dagoth Ur, Azura and Vivec, not to mention the Emperor's hardnoses intelligence service, should leave no doubt that something supernatural is up.
His previous attempts had all failed. That doesn't mean he just kept trying the same failed batch. It means you got the newest stuff, with all the tweaks and adjustments that come with that, and it happened to be the one that worked. You think he just arbitrarily was giving the same potion to everyone who came to him looking for a cure even though it only ever succeeded in killing them? That it's not a big deal outside this single instance only indicates that the ingredients are either too rare or the process too complicated to be effective on a widescale, or it's simply a matter of Beth not implementing a proper consequence to that event.
Your actions don't have to follow the prophecy, incidentally. There are backdoor methods to completing the main quest. That it's possible to follow the steps of the prophesy is irrelevant. Your ability to run errands for ashkans and duel great house leaders doesn't require any prophesy. It only requires you be capable. It's only proof that you did those things, not that they were required or that you couldn't have done them sans prophesy.
Dagoth Ur, Azura, Vivec, the ashlanders, the great houses, etc, all had skin in the game already. They have their own motives for playing along with the prophesy without needing the prophesy to be true. Dagoth Ur doesn't want anyone stopping his plans so he'll work against you simply because you're calling yourself (or others are) the Nerevarine. If you are or not is immaterial to him. You're still a threat. Azura wants the heart destroyed and the tribunal stripped of their godhood. That's why she cursed the dunmer in the first place. If you stand a chance of fulfilling that goal, no reason for her not to recruit you. Vivec originally has reason to oppose you, as the return of the Nerevarine bodes ill for the tribunal. Later you become a necessary component in his plan to defeat Dagoth Ur. None of their actions or responses to your actions require you to
actually be the Nerevarine, only that they perceive you as capable of doing what the Nerevarine is fortold to do.