get into a lather

get into a ˈlather

,

work yourself into a ˈlather

(British English, informal) get anxious or angry about something, especially when it is not necessary: Look, don’t worry! There’s no point getting yourself into a lather over this!The idiom originally described the heavy sweat that you can see on the coat of a horse that has run very hard as a mass of white bubbles, like lather, the bubbles produced by mixing soap with water.
See also: get, lather