"Everyone" makes the answer is a bit more complex than "yes" or "no". Yes, given the first three 'under conditions of:" above a second opinion would be strongly recommended. However, "Not being able to see" an Head and Neck cancer (ENT) specialist seems to be contrary to a requisite for any comprehensive treatment plan. Given the healthcare disparities and treatment we have in the US (for many reasons) I would add that at least a consult with someone at a major academic treatment center would be in order (Skype, e-mail, etc. offer options). For head and neck cancers the quality of life after treatment can be dramatically and profoundly effected by the treatment that is/was received. But as with any other diagnosis and treatment plan age, comorbidities, and other factors must also be considered. I hope this perspective helps answer your question.
ot only should one seek a second opinion, but also a third opinion. It is better to have a majority opinion than to have to choose between two. I would go to and/or seek advice from a specialist in oral cancer. The specialist would want to see x-rays and any other objective data. Don't depend on one person being correct 100% of the time. I hope this helps.