Hi, did you happen to find out what the problem is? I’m currently going through the same thing. Lots of saliva under my tongue. I hope to hear from you soon. Thank you.
Hello and welcome to the forum. Sorry for the delay in response but am happy to try to help. We always recommend seeing your doctor for evaluation when you have a concern but especially when it has been ongoing for some time as you describe. Hypersalivation is a condition. Saliva provides an important function but when it is too much, it is often due to an underlying reason. This is what you need a doctor for. Causes of excessive saliva production could be a result of :
morning sickness or nausea during pregnancy
sinus, throat, or peritonsillar infections
poisonous spider bites, reptile venom, and poisonous mushrooms
false teeth
ulcers, inflammation, or pain in the mouth
poor oral hygiene
severe infections such as rabies or tuberculosis
severe or sudden pain
regurgitation of saliva during heartburn
jaw fractures or dislocation
https://www.medicalnewstoday.com/articles/318728#Causes
They do treat this in a variety of ways. But first the underlying reason needs to be determined. Actually, drinking more fluids helps decrease saliva production as does rinsing the mouth with mouthwash. If you haven't been to the dentist in a while, this is something else to consider. A tooth cavity can cause temporary hypersalivation. Reflux is another common reason for it and is not terribly difficult to treat. https://www.healthline.com/health/dental-and-oral-health/hypersalivation
Let us know if the problem is still happening, what you've tried and if you have yet been to a doctor.