I don't know a term denoting a microphone usually held on speaker's side of the face. See following image that shows in white:
I googled images pertaining to the types of microphone, but that did not help. It shown me following results, that does not include the thing, of which I want the term.
After encountering such types, I had a doubt, whether the term which I want to know is just "microphone" or not.
Sample sentence can be:
I saw Sandeep Maheshwari giving a comprehensive lecture in front of a large audience via a device held on his face, called a _____ ?