Sure, these are all possibilities. With sufficiently able individuals who are sufficiently informed, we simply create the treatment and permit the individuals to select as required. For instance, the patient can choose to either suffer temporarily with the hope of the future positive outcome for the suffering or they can choose the immediate solution.
If the patient is not sufficiently able to choose due to being mentally unable and the drug is likely to bring them back to lucidity, then it is obvious that bringing them into a lucid state is the logical path, so we should recommend administering the drug.
For my part, I've noticed that people who dwell on these traumas have a hard time. Meanwhile I've suffered numerous things that many of these people claim have led to debilitating mental illness and I operate in a space of mental comfort. So, should I encounter another trauma event, I'll take the forgetting drug.
And presumably you, believing otherwise, should refuse it.
P.S. Here's a thought experiment for you: What if the MMR-2 vaccine instantaneously kills people at the age of 60. It was introduced in 1963 and this year is 2022, so the first recipients are not yet 60. So you simply cannot prove that it does not do this. You have a son. How do you reason whether to risk the possibility of instantaneously killing your son when he hits 60 vs the risk of him contracting any of Measles, Mumps, or Rubella?