acne vs pimple

acne and pimple both are nouns.

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

As nouns, pimple is a hyponym of acne; that is, pimple is a word with a more specific, narrower meaning than acne:

acne: an inflammatory disease involving the sebaceous glands of the skin; characterized by papules or pustules or comedones
pimple: a small inflamed elevation of the skin; a pustule or papule; common symptom in acne

Other hyponyms of acne include acne rosacea, rosacea, acne vulgaris, hickey, zit.

acne (noun)	pimple (noun)
an inflammatory disease involving the sebaceous glands of the skin; characterized by papules or pustules or comedones	a small inflamed elevation of the skin; a pustule or papule; common symptom in acne