Hello.
Thank you for posting your query at DoctorSpring.com
Will it be possible for you to upload a picture of what you're trying to describe?
Normally a coated tongue can be due to some infection. But since you do not have any other symptoms, it does not seem to be a cause for worry. At times it happens on its own and settles down within 2 weeks. But if it persists beyond 2 weeks, it needs to be examined.
Some of the causes are lichen planus ( it is a chronic disorder and hence can be ruled out ), leukoplakia, a benign condition where there will be white patches in the mouth and the tongue, is a common condition.
Can happen in diabetics too. One last cause can be due to oral thrush where there will be a history of recent antibiotic or steroid usage. It renders the patient immuno compromised and hence an yeast infection develops.
Since you're observing it is settling down on its own i won't recommend any medicine as of now. Based on the picture that you send, i can help you further.
Regards.

Hello.
Thank you for the follow up.
From the picture that you sent today, it does not seem to be widespread. Its actually not very clear but does not look like anything alarming.
I will advise you to get a LFT done. Sometimes due to slight dysfunction of the liver, and slight indigestion such coating can be present. The etiology is not well known but it is associated with a white coating on the tongue and gastric symptoms may/ may not be present. Do you have any after taste in the mouth?
Just continue the the cleaning of the tongue with the baking soda solution
Once you have your LFT report let me know.
Hoping to hear from you again,
Regards.