The face with thermometer emoji is a yellow, neutral face with closed eyes, a small, frowning mouth, and raised eyebrows, shown with a red thermometer placed in its mouth as if taking a temperature reading.
It is often used to convey a sense of illness, sickness, or medical concern, and it can be used to show that you are feeling sick or unwell, or that you are monitoring your health or the health of others. It can also be used to express a sense of concern or caution, or to show that you are taking steps to prevent the spread of disease.
Differs from other smileys conveying illness, such as ? Nauseated Face (appearing as if it's going to vomit) or ? Face With Head-Bandage (physical injury).
Face with Thermometer was approved as part of Unicode 8.0 in 2015 and added to Emoji 1.0 in 2015.
U+1F912
? Face with thermometer