Your picture is very helpful. From the appearance, I believe you have a "cold sore", which is the common term for oral herpes, or HSV-1. While this is not a dangerous condition, it can be very bothersome. Canker sores generally occur only inside the mouth. Herpes sores are common and often occur on the lips, mostly outside the mouth. This is a viral sore that can be triggered by fatigue, weakened immune system (a cold, for example), stress, extreme cold, sunlght or injury. While it's certainly not a dangerous medical condition it is quite contagious. So, avoid touching the area without thoroughly washing your hands afterwards. Also, avoid contacting anyone with the affected area, as skin to skin contact with an active sore can spread the virus.
Treatment options include a topical ointment called Abreva, which shortens the duration of the sore. Oragel is also commonly used, but while it makes the sore more comfortable, it will not speed u healing time, as Abreva generally does.
Without treatment a cold sore generally lasts 8-10 days.Abreva does have FDA approval for shortening this time span.
Please let me know if you need any additional information to answr your question. If not, I'd appreciate a positive rating.