I have a painful little white headed bump on the inside of my bottom lip, it just appeared one day and i don't know what it is?

Could be many things: It could be a traumatic papilloma. Non cancerous. It could be a mucocele which is a clear build up of saliva from a damaged salivary duct. This can have a white surface if you accidently bite it. If it does not go away in a few weeks have it looked at by your doctor and have your teeth examined at the same time.

Canker sore: Stress both physical and emotional can bring on a canker sore. It is painful and lasts about 10 days.Otc gel or cream can be applied.

Don't know: It could be a canker sore or some other other benign problem. It should go away in a few days to a week if it doesn't see your dentist.