Thanks for posting your query.
Since you gave a H/O habit of tobacco chewing
for about 3 years,the sore appeared on the cheek,may be lesions of leukoplakia.
I would advice you to quit the habit of tobacco chewing completely.
Apply mucopain gel on the affected site.Chemotherapy
or surgical excision of the lesion is necessary to remove the infectious sore completely.
Vitamin A as well as iron supplements
has to be administered.
Maintain oral hygiene