I’ve been playing dark souls for the first time, and I didn’t understand that I was supposed to bring fire keepers souls to the NPC to actually get the flask upgrades.

From a bit of reading online, it sounds like there’s no way to correct this in the game itself and I’m just kinda screwed.

I’m too far in to restart, and I’m wondering if anyone knows a mod or some other method to undo my mistake? Either to give myself the souls I consumed or to upgrade the flask without them?