Smallpox affected Korea through visitors - and so the Smallpox god became known as "Son-nim" Honored Guest. Over time, as smallpox's impact was thankfully lessened, she became an overarching goddess of illness and disease.
There are many variations of the disease god, like all our gods. It is specific to region, lineage, and even down to the mudang.
Byeolsang Aegisshi, 해화 무당
Byeolsang Aegisshi (and all other gods of disease) prevent illnesses from coming "inside" of one's home or body from the outside. They eradicate diseases and illnesses, although usually, it is smallpox and measles and other skin infections. She can ward off evil and protect you. She is one who is found in some mudangs' pantheons.
EPITHETS:
She Who Hides Her Face
She Who Brings Good Health
She Who Gives Illness
She Who Takes Away Illness
The Honored Guest
The Visitor
The Honored Visitor