I agree with what the others have suggested - get a biopsy first. I've had a few discussions with my doctors (2 different ENTs) and they would rather do surgery after cancer is confirmed via a biopsy (a small sample). This way the tumor is more intact and is easier for them to surgically remove it with the goal of getting clean margins (a wide area of healthy tissue surrounding the tumor). Many biopsies can be done in the office. An oral surgeon can do this, but if you can get an appointment with a ENT with oral cancer experience, it is probably better to have it done by the ENT.

You mentioned you had an oral cancer screening at your dentist that showed abnormal cells. How did the dentist determine they were abnormal? Was he using a Velscope or other "light" device that aids it detecting abnormal cells? These devices are great tools to help identify suspect tissue, but that also depends on the experience of the doctor who is using it. They only sure way to confirm if it is cancer is via a biopsy.

Take it a step at a time. I sure hope it is just a lump!