It seems like a plaque (Lichen planus) kind of lesion
No need to worry or panic
Kindly consult nearby Oral and Maxillofacial Surgeon or contact me and / or dentist
Get it thoroughly evaluated and biopsy if required
It can be reversed with medicine only once confirm the diagnosis
Next Steps
visit nearby dentist
get investigation done including biopsy and diagnosis
Health Tips
maintain oral hygiene
don't try to remove it by any instrument