Spells (not scrolls) dissapear. Any way to get them back?

[Ermac]

Nope, i checked the spellbook multiple times, im positive it's not there :/

And could it really be that there's only one event in the whole game where you can get it? I mean what if someone hadn't checked the lost chronicles and didn't found it? Or used it up as a scroll without making a spell?

I don't think the creators would leave such holes in the design..