ETA great explanation from Merriam-Webster: https://www.merriam-webster.co.....f-hot-mess
"The term hot mess originally referred to a mess that was literally hot—mess in this case being related to the kind served in a mess hall. Before it was anything else, mess was a word for a quantity of food. (It traces back to the Late Latin missus, meaning “course at a meal.”) Later it referred to a prepared dish of specifically soft food. And a hot mess was originally a hot dish of such food.
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Hot mess spent the 20th century mostly shut up in books written the century prior (not entirely, though: “Now, ef I says the word, yo’ll be in a hot mess in about one minute!,” a character threatens in a 1907 issue of Pall Mall Magazine, for example). But in the early 21st the term sprang forth with renewed vigor.
It’s not at all clear what made hot mess into such a hot 21st century linguistic commodity, but evidence of its progress is everywhere. And the term continues to evolve: while earliest 21st century uses are almost uniformly unflattering—the emphasis is on the mess part—the term has developed a newer meaning, referring to a person who’s disorganized, disheveled, or self-destructive but who is also at the same time “hot,” as in attractive or sexy."
