TL;DR zilactin. It's basically crazy glue with a base in it to piss off the pH of canker sores. Covers 'em up, heals 'em up, best stuff there is.
I started getting what my parents called "herpes sores" when I was about eight. My parents set me aside and told me the tragedy of how they'd contracted oral herpes while in the Peace Corps in Brazil, likely from a shady dentist, and that it was truly unfortunate, but it could be treated and I was a big boy now so I had to be tough.
The treatment they'd learned for "herpes sores" in the Peace Corps in the '60s is to take a bamboo skewer, like what you use for barbecues, and wrap the tip in about a q-tips' worth of cotton. You then dip this in battery acid. Literally, you pop a maintenance cap off an automotive battery, eyedropper out about 50ml of sulfuric acid and keep it in a glass bottle in the medicine cabinet. The pokey, cottony, acidy spear is then lanced into the "herpes sore" until it bleeds. You repeat this until there is no white left, just angry, raw, bleeding-black (because of the acid) flesh. Fortunately, the eradication of the sore coincides with the sensory overload of being stabbed in the gums with a bamboo skewer dipped in battery acid so by the 3rd, 4th 30-second session you no longer feel much pain.
(which is okay the previous treatments are more than enough)
My father proudly told me about the age of 12 about the friend of his he treated who had "a couple hundred" "herpes sores" in his mouth, all of which my father treated, such that the man could again eat a sandwich without pain. I learned that they come out with stress and by the time I was 12 or so I was treating my own "herpes sores" - wrap the spear, dip the acid, bleed black, perhaps repeat the next day, perhaps the next, but eventually it goes away. So life continued until I went off to college.
The first canker sore I got in college was under my tongue. I didn't have a car at the time. I had to ask around in the dorms until I found a guy willing to let me siphon off some of his battery with a soda straw taken from the cafeteria. I kept the acid in a Jack Daniels miniature bottle. I can't recall what i did for the bamboo skewer. It's possible I just bought some, more likely I stole one out of a package at the grocery store (who steals a single bamboo skewer, after all? They keep them in ziploc bags for like a dollar).
A problem with stabbing yourself with an acid-dipped bamboo skewer, of course, is you need something to stab against. Gums are easy; there's bone. You push until you can't push anymore. Under the tongue? Another matter. Suffice it to say that one day, two days, three days, four days, five days, six days the damn thing kept getting bigger. It was like a cancer no chemo could cure. So after about ten days of agony, with this "herpes sore" under my tongue roughly the size of a dime, I capitulated and hoped that Student Health could help me out.
I sit down with the nurse, embarrassedly relate my family history of "herpes" and our "treatment." She looks at me, impressively stone-faced, then asks to see under my tongue. I open my mouth.
"That's the biggest canker sore I've ever seen," she says.
"Canker sore. Herpes sores are on your lips. They're external. You have a canker sores. Everyone has canker sores. I've never heard of them being treated by stabbing yourself with battery acid."
"Go to Walgreens and buy this stuff called Zilactin. It's about four bucks."
And that is why, dear rd95, I can endorse Zilactin with no hesitation. I have been to hell and back treating canker sores and in LA, you can't get Zilactin. Kanka, anbesol, all the rest of them are glue with anesthetic in it. Zilactin actually has a "battery acid" component (which disturbs the pH of the canker sore, which promotes healilng) without requiring a "battery acid" sacrifice.
Collecting starts when there's a reason for each item and each item is unique. Hoarding starts when you just want more.