canker vs canker sore

canker and canker sore both are nouns.

Word	Noun	Adjective	Verb	Adverb
canker	Yes	No	Yes	No
canker sore	Yes	No	No	No

As nouns, canker and canker sore are synonyms defined as:

canker and canker sore: an ulceration (especially of the lips or lining of the mouth)

canker (noun)	canker sore (noun)
a pernicious and malign influence that is hard to get rid of	an ulceration (especially of the lips or lining of the mouth)
an ulceration (especially of the lips or lining of the mouth)
a fungal disease of woody plants that causes localized damage to the bark

canker (verb)	canker sore (verb)
infect with a canker
become infected with a canker