What should I do if I open a room in a hotel with my girlfriend and the last resident hits me at the door with something?

You can sue for compensation or negotiate with the hotel.

According to your situation, it is generally not a big problem for glass to scratch your feet, unless it is iron products or stainless steel products, especially rusty scratches, which are easy to cause tetanus infection. It is recommended to apply disinfectant after cleaning, and do not touch water at ordinary times to avoid infection. If you are not at ease, you can also take preventive measures against tetanus.