papule vs pimple

papule and pimple both are nouns.

Word	Noun	Adjective	Verb	Adverb
papule	Yes	No	No	No
pimple	Yes	No	No	No

As nouns, pimple is a hypernym of papule; that is, pimple is a word with a broader meaning than papule:

papule: a small inflamed elevation of skin that is nonsuppurative (as in chicken pox)
pimple: a small inflamed elevation of the skin; a pustule or papule; common symptom in acne

Other hypernyms of papule include hickey, zit.

papule (noun)	pimple (noun)
a small inflamed elevation of skin that is nonsuppurative (as in chicken pox)	a small inflamed elevation of the skin; a pustule or papule; common symptom in acne