What can i do for a kanka sore in mouth?

Warm saltwater rinse: You can rinse with warm salt and you can also try an over the counter cream called zilactin and put it on the canker sore. It will sting at first but it forms a bandage that lasts for several hours. You should be able to find it in a drug store.

OTC products: Avoid hot, spicy and hard foods which can be very irritating to the sore area. Use an over the counter medication an apply it to the affected area. It will eval in 10 days.

Canker sores: Personally, when I had them in the past, I just rode it out. If they are persistent or severe, a good article on the subject can be found at: http://students.umw.edu/healthcenter/files/2011/08/Aphthous-Ulcers.pdf