Hello. What a shock for you as a parent to be considering this diagnosis in a 17 year old child.
Until he has had a biopsy of the area you don't know what you actually are dealing with. Try to take some deep breaths and take it one day at a time.It can be very frightening to read up about stages and treatments on the net. You may yet be worrying unnecessarily. I would get him to an experienced ENT who deals with head and neck cancers to get this done. I would also push for the earliest appointment you can get - just to let you know either way. I'm sure your mind is racing with "what ifs" and "what abouts".
As Christine said, please , please get your son to stop smoking.
Come here often for advice, to rant and let us know what eventuates. Wishing you all the best,
Tammy

Caregiver/advocate to Husband Kris age 59@ diagnosis
DX Dec '10 SCC BOT T4aN2bM0 HPV+ve.Cisplatin x3 35 IMRT.
PET 6/11 clear.
R) level 2-4 neck dissection 8/1/11 to remove residual node - necrotic with NED
Feb '12 Ca back.. 3/8/12 total glossectomy/laryngectomy/bilat neck dissection/partial pharyngectomy etc. clear margins. All nodes negative for disease. PEG in.
March 2017 - 5 years disease free. Woohoo!