After staying in the express hotel, I got a rash on my thighs, legs, arms and waist, which was very itchy.

Hello! It's best to go to the hospital for an examination, see what the reason is, and find out the reason for symptomatic treatment, because many skin diseases have the same symptoms and can appear like you. I suggest you: in this case, he may be allergic to the skin caused by the environment there, or eczema. In order to diagnose what skin disease it is, I suggest you go to the hospital to find an experienced doctor to check it carefully and find out the reasons for symptomatic treatment.