I'm going insane here. I'm doing the well section of Ikana Canyon, and I managed to get every item needed except a blue potion. Now it's the third day, and I really don't have time to go get the Mask of Scents and a Mushroom and wait for the witch. I'll lose all the stuff I have already that I spent time running around collecting. I have to say this game really does try the patience.
Is the blue potion really necessary to proceed with the story in the well, or can I get by with everything except it? And if so, is there any other way to get it besides Koume? I read that there's a deku scrub who sells it, but I can't find him at the moment...
The blue potion isn't really needed, you don't have to completely explore the well.
All you really need is 5 Magic Beans, a fish, a Big Poe (which you can get to with 10 Deku Nuts and 10 bombs), and a bottle of milk. You'll miss out on a couple chests with rupees, but other than that you should be ok. The main function of needing the Blue Potion is if you bring one, and the 5 Magic Beans, you can get everything else you need in the well itself. Without the potion you won't be able to get the hot spring water, meaning you can't get to the cow to get milk, so you'll have to get that from someplace else.
I am Fado of the Kokiri tribe. I know I appear to you as a child, but the eyes can oft deceive. I am a most esteemed sage.
Yeah, if you don't mind paying 100 rupees (instead of 60 from Kokate, and the first one's free), there is a Business Scrub that sells Blue Potions. He's right near the entrance to Sakon's hideout -- simply follow the land that runs alongside the Ikana river.