Thanks for asking the query,
Pain and discolouration of gums indicates severe infection of the gums known as Gingivitis
Oral cancers are associated with chronic use of tobacco chewing
consists of white to dark patches, ulcerations, lumps in the oral cavity and firm to hard swellings.
I would suggest you to get a checkup done by the Dentist
, take an OPG radiograph , x-ray along with biopsy report will give the exact diagnosis.
Quit the habit of tobacco chewing, start taking antioxidant tablets
Go for symptomatic treatment of complete mouth scaling, polishing and root planing.
Hope this helps out.