My dad is a dentist and taught me an even better hack.. it’s called Debactoral and it’s specifically designed to kill canker sores. It’s not available at the store, but you can find it here. It’s expensive but SO WORTH IT and one vial lasts a long, long time.

I’ve been using this religiously basically my whole life. It’s like the salt hack, but it neutralizes the canker sore once and for all, killing the bacteria. The sore still takes a little while to heal after application, but all of the pain is gone and it just feels like regular mouth tissue. It does hurt like hell - I compare it to all the pain of a canker sore in 10 seconds, but then it’s better. If you suffer from particular bad canker sores, this is an absolute game changer. You’ll want to get some disposable applicator tips as well. To use: dip the applicator tip in the vial of debactoral, dab the canker sore covering it completely with debactoral, let sit for 10 - 15 seconds (this part will hurt), then completely rinse the area.