rub petrolium jelly on it
A chancre is the first sign of syphilis. Syphilis is called the 'great imitator' because it can present itself in ways that make it appear to be something else. A chancre will always look like a sore...
Syphilis
Many alternative therapies for canker sores try to heal the existing sores and prevent their recurrence.
Contrasting hot and cold local applications can increase circulation to problem areas and help flush out waste products, speeding the healing process.