A consul general is a diplomat who runs a consulate. A consulate is like a embassy, representing a foreign nation. A nation has one embassy in a host nation but may have any number of consulates as agreed by the host nation.
Actually, an embassy is a presence of a foreign nation whose sovereignty is recognized by the host nation. It is an actual representation of a foreign government in the host nation. A consulate’s office doesn’t have the same standing or privileges that an embassy does and is merely a home government functionary presence to assist expats and citizens from the home nation with documentation and legal matters arising in the host nation. They generally aren’t considered a diplomatic presence.