Worsen
Worsen , transitive verb
1.
To make worse; to deteriorate; to impair.
It is apparent that, in the particular point of which we have been conversing, their condition is greatly worsened.
2.
To get the better of; to worst. [Rare]
Worsen , intransitive verb
To grow or become worse. — De Quincey
Indifferent health, which seemed rather to worsen than improve.