Yes, if you stop using Baking soda for more than 15 or 30 days it will come back because your place is infected with malassezia yeasts, not only you, you house, pets, clothes and your bed pillow is populated with it, your hair have billions of it and scalp too. So keep using it, BUT start decreasing the amount of it until you find a stable dosage of baking soda.
About drink, I only drinked it for 30 days and I never had to drink it again. Be careful don't drink too much or you will drop the acidity of your stomach and this is not good !