Welcome Ontarioguy,
My first biopsy was negative, I had a white patch under my tongue. Six months after it was removed, I had a white line of what looked like scar tissue. My original oral surgeon said it was nothing when I showed it to him. When it ulcerated and became sore, I went to the dentist and he hustled me off to another oral surgeon. I had surgery and it was SCC, T1 thank goodness but by the time the ulcer showed up it was deep enough into the floor of my mouth that I had to have a graft. I don't think you should wait 3 weeks to see your ENT. Call his office, speak to the nurse and they will work you in is my bet. I am assuming here that didn't have radiation since you didn't mention it.
My vote? Call the doctor. It can't hurt and can definitely help. If he can't see you himself, maybe a partner, PA or ARNP can take a look and go get him if needed.
Sincerely,
Lisa
PS- I also used a digital camera and took pictures of my neck scar and emailed it to my doc so he could keep an eye on it after he revised it. Maybe you could try that if they can't work you in today.