I used someone else's blade when I was in the hotel. If I am an AIDS patient, will I be infected?

What kind of blade is this? If it's a fruit cutting blade, it won't, because HIV is exposed to the air and survives for a few seconds at most, and human saliva has a certain killing effect on it. There are three kinds of AIDS transmission, blood transmission, sexual transmission and mother-to-child transmission.

Razor. That won't happen.

You can't even shave your head, because even if there is HIV there, it has already been killed by the air.