hickey vs erythema

hickey and erythema both are nouns.

Word	Noun	Adjective	Verb	Adverb
hickey	Yes	No	No	No
erythema	Yes	No	No	No

As nouns, erythema is a hypernym of hickey; that is, erythema is a word with a broader meaning than hickey:

hickey: a temporary red mark on a person's skin resulting from kissing or sucking by their lover
erythema: abnormal redness of the skin resulting from dilation of blood vessels (as in sunburn or inflammation)

hickey (noun)	erythema (noun)
a temporary red mark on a person's skin resulting from kissing or sucking by their lover	abnormal redness of the skin resulting from dilation of blood vessels (as in sunburn or inflammation)
a small inflamed elevation of the skin; a pustule or papule; common symptom in acne