herpes
Medical term for herpesvirus infections; commonly used in compounds like 帯状疱疹 (herpes zoster) or 口唇ヘルペス (cold sores).
I have a cold sore and my lip hurts.
Herpes is caused by a virus.
herpetic keratitis
Borrowed from German 'Herpes' or English 'herpes', ultimately from Latin 'herpes' and Ancient Greek 'ἕρπης' (hérpēs, 'a creeping skin disease').