Thanks for posting your query,
There are a number of lesions in the mouth that are consistent with what you describe. They include: simple bruises, amalgam tattoos, or a melanocytic nevi
you should see your primary care
physician or your dentist
to have the area examined and determine if a biopsy
is warranted. It might not be anything serious. Good luck for next week.
Please see your own dentist/doctor for a proper diagnosis and plan your treatment according to that
I hope this information has been both informative and helpful