Was my fasting valid for the day on which I swallowed drops of water during prayer in Ramadan, and do I owe expiation?

Drops entering the mouth do not invalidate the fast unless any of them intentionally reach the throat. If the fasting person intentionally swallows these drops, then he must make up that day; otherwise, he is not required to make it up, and his fast is valid according to the majority of scholars. If there is doubt about the invalidation of the fast after the day has ended, there is no making up for the fasting person because doubt after completing an act of worship has no effect. Expiation is not required in any case.