The Consequences of the Events at Mount Doom

[Aramacil]

But I don’t understand something.

Why did Frodo’s painful wounds play up when it was that time of the year again, 1 or 2 years after the ‘incident’ at Weathertop and when he is near it (see macaroni’s quote).
Was the wounding at Weathertop so important? In the books there is not much said about it after he recovers in Rivendell, until the last chapter. Suddenly he almost dies because of those wounds, my only conclusion can be that it was indeed all the wounds combined.