A few days ago I drank from a cup in a hotel room in Kunming, but my lip was split. Could this have infected me with AIDS or something? !

No.

HIV is transmitted through blood and body fluids. HIV will die soon after leaving the human body, so there is no need to worry about whether you will be infected with the virus because of your cracked lips.

As for other diseases, what is more terrifying than AIDS?

So don’t worry, usually rinse the cup with boiling water before using it. Personally, I usually drink mineral water when staying in hotels. Never use hotel cups.