If it is not seen otherwise by a naked eye, then it is unlikely to be a papilloma (because surface alteration will occur as a rule in papilloma)...... more likely it could be a mucocele caused by trauma to the lower lip during biting..... one thing you could have understood your self (with the history of the lesion not healing itself for the last 8 to 9 months) is that it is not going to regress on its own..... you will require removal of this lesion by an oral surgeon..... nonetheless, these are just opinions based on your description..... the best diagnosis can be made by the dentist who performs a proper clinical examination of your lesion..... Regards.....
It could be a pappiloma or a mucocoele caused by collection of saliva in the mucosa typically after biting into your lower lip by the upper anterior teeth . Removal of the same by a Diode Laser is the easiest way to cure it. Feel free to consult Laser Smile Care Centre. God bless.
Well it's better you consult a general surgeon and get it examined as we need to see of its something we need to worry about...cannot suggest you without examining so best would be to consult a gen surgeon....thank you