Hello and Welcome to ‘Ask A Doctor’ service. I have reviewed your query and here is my advice. From your explanation it looks like a mucocele or a mucous cyst. Mucocele is a false cyst caused due to injury to the minor salivary glands present under the tongue in abundance leading to spillage of mucous and its accumulation into the soft tissues leading to formation of a fluid filled lump. You need not to be worried about it as it is harmless and will not cause any serious problem rather than being uncomfortable. It is worse during eating as during eating the saliva flow increases and it fills up which gradually goes down in some tine post eating. Many a times the mucocele ruptures by itself by spilling its contents into mouth and gradually heals but in case if it does not resolve surgical removal is the only left out option. As of now you should not only do salt water rinses but should take a concentrated salt water solution and gargle at least 3 to 4 times a day. But in case of large mucocele or if it does not get better or continue to grow in size surgical removal has to be done and you need not to worry as it is not a very extensive surgery and can be done with ease and success by an oral surgeon. For a correct diagnosis Oral Physician should be consulted. Hope I have answered your query. Let me know if I can assist you further. Regards.