My sim got this too after the latest update and I cant remove it with mods bc it keeps coming back. Ive tried curing him but that gives him a moodlet saying he took it without having an ailment. The ailment does go away while that moodlet is there but comes back after its gone. There is no option to go to a nateuropath (sorry bad spelling) and he has no paint on his skin like it should show. Its really annoying bc he cant sleep, thats the only thing that is in line with the ailment.
i use mods but he is like this even if I remove all of them and play vanilla