Mary,
Christine answered your questions best. I don't completely know why you weren't referred to an oncologist, but can guess since certain stage, usually early stage, no clinical nodes or one, oral cancers can be treated by resection with or without a neck dissection. Depending on the pathology, number of nodes cancerous, there may be a need for chemo recommendation, and that's where the oncologist comes in. If your center has multidisciplinary care, your case is usually presented to the tumor board where all the doctors and specialists in head and neck cancer attend, including the oncologist, and agree on your treatment.
I've had oncologists that specialized in head and neck cancer, and nice to see them know about this disease when we often have to educate many healthcare professions, including doctors not associated with this cancer, which just happened to me yesterday. It's hard to say who has more knowledge. I had a radiation oncologist with surgical background who I thought was the best.,I guess each has their own area of expertise. Sometimes there seems to be one person directing your care, and have been through each from Medical oncologist to ENT to radiation oncologist depending on your need.
Good luck next week