Hi dear , As per your query you have red spot on your tongue for about a week . Well there is no need to panic because there can be many other reasons responsible for symptoms you mention like aphthous ulcer , viral infection , glossitis , vitamin deficiency , lichen planus or due to some medication . But there is very rare chance of this to be cancer . I would suggest you to maintain proper oral hygiene , do warm saline rinses and start multivitamin supplement for few days . If condition persist even after a week then consult oral pathologist for proper examination . Doctor may prescribe antibiotics or anti viral depending upon the diagnosis . Hope your concern has been resolved. Get Well Soon. Best Wishes, Dr. Harry Maheshwari