Hello Hmarynka, 

I am no medical expert but it is extremely rare for a child to develop mouth cancer so it is more likely that your child has something that is benign and can be easily dealt with like a mucocele for example (I've had one myself in the past!).

You've done the right thing though to book an appointment with the GP as only the doctor will have the expertise to tell you exactly what it is and how to treat it. But try not to worry too much about it as hopefully your GP will give you reassurance on this very soon. 

I hope you are doing ok yourself after having dealt with thyroid cancer and that you have recovered well. 

Best of luck with your boy's appointment and best wishes, 

Lucie, Cancer Chat Moderator