Hi..
Welcome to HEALTHCARE MAGIC..
I have gone through your query and can understand your concern..
As per your complain dark patches over the tongue can be due to excessive melanin pigmentation over the tongue, it can also be due to
black hairy tongue which is due to debris accumulation over the tongue, side effect of any medication,
allergic reaction, while can also be cancerous like
Malignant melanoma..
You need to consult an Oral Physician and get evaluated and he can do a thorough clinical evaluation and investigations like Biopsy can help in diagnosis and treatment can be planned accordingly..
As of now you can keep the tongue clean by using a tongue scraper, gargle ith 1:1 solution of
hydrogen peroxide and water, chew sugarfree chewing gums to improve salivation and maintain a good hygiene..
Avoid smoking,
tobacco chewing and drinking..
Hope this information helps..
Thanks and regards.
Dr.Honey Nandwani Arora..