@Cybik The thing is, as long as those particles remain in the lungs they will continually cause damage. That is why there is no cure. It would have required surgery or some other such magical interference to cure this kind of condition.
There is no medication on the market that will "speed up" regeneration either, so there is nothing to say about creating something that can promote cell growth to regenerate the damaged cells faster than they could be damaged. That would be like inducing a tumor.
Suspending my disbelief or not, this is very handwave-y of the author. Did they even try to look up the condition they were trying to treat? Because there is no cure, and it would've been more accurate to say she used her past-life to replicate game-potions or elixirs. She made it sound like this person recreated a medication from the modern day, when in reality it would be more accurate to say she produced a medication that is surgery in a pill.