The emoji of a wide open mouth with a single drop of sweat on one side of the forehead represents awkwardness, tension or embarrassment. This emoji is also used to express exercise-related messages or even relief. Sweating Emoji can mean from "Ops! My mistake!" to "What an awesome and ...
You will also see this emoji accompanying posts about anime because, according to Winnie Liu of the Factorialist, “the giant sweat drop above the brow has traditionally appeared in Japanese animation…to indicate awkwardness, frustration, embarrassment, and sentiments like What the heck?” Just ...