Is there a penalty for practicing medicine in a hospital without a license, but without causing any harm? Or does nobody care at all?

It is not illegal for hospitals to employ undocumented doctors. Medical graduates with medical-related qualifications are required to have a probation period of ten months in the hospital and pass the examination. Your job category is probation. If the hospital arranges you to work independently, it is illegal in the hospital system. As a person who is not qualified as a medical practitioner, you will not have the ability to judge whether it is illegal or not, otherwise you will not consult online. You don't have the ability of diagnosis and treatment, so all the damage caused by this will be borne by the hospital. But you and the hospital belong to the employment relationship, and the hospital will definitely have problems in the work system.