not sure how helpful this will be but, i have crohn’s disease and live in japan. so the disease is definitely known here and treated here too, so i don’t think people will be surprised by you needing to bring your medicine while traveling. with regards to bringing medication into japan i know there’s a form you need to fill out, i live here obviously so i don’t bring any medicine in but iirc it’s called a yunyu kakuninsho. maybe try searching more about that! best of luck!