Raid events are not rerun.

There is no way to get the weapons from those events.

There is a way to get missed Eidolons, the Eidolon Point Shop or whatever. But it is rather expensive, you basically trade 4 event SSRs in for one previous raid SSR.

There is a way to get missed pity SRs that are given from raid events, but your chances are miserable. Much later on, you can buy one "raid kamihime weapon" ticket per Advent.