Why do I have a big white sore inside of my lip and how can I get rid of it asap?

If it is a canker sore, it will go away in a day or less, usually. Think about what you ate and the next time you get one, think about what you ate and so on… I get them from eating walnuts. It doesn’t seem to happen if the walnuts were boiled.

this is the first time i have had one, will i continue to get them?

Believe it or not, canker sores on your lip can be caused just by friction from your teeth. Making sure you brush often will keep your teeth clean and keep cankers away, and it wouldn’t hurt to use an antiseptic mouthwash. As already stated, they can also be caused by certain foods - specifically acidic or salty foods.

Canker sores and you might want to talk to a doctor.

canker sores. you can get a special type of medicine at a drugstore or grocery store, and try not to eat acid-y foods. you can use warm water with salt in it[salt water] as a mouthwash thingy, just swish it around in your mouth, it usually helps.

I still get them but not as often as when I was a teenager. I hardly ever forget that walnuts cause them to happen to me any more. I probably suffer with them less often than once a year now.