Hi..
Welcome to HEALTHCARE MAGIC..
I have gone through your query and can understand your concerns..
As per your complain a lump over the gums that increases in size and then gradually ruptures and releases pus seems to be due to ether
tooth infection or
gum infection..
In case if the tooth over which it is present has decay in it there is a possibility that you have a recurring
dental abscess due to infection reaching below the toot tips of the tooth and causing pus formation..
In case if it is not the case then it can be due to deep infection in gums due to accumulation of infectious deposits over the teeth..
Sinus issue or
thyroid goitre does not seems to be due to it..
I would suggest you to consult an Oral Physician and get evaluated and a thorough clinical evaluation and investigations like x ray can help in diagnosis and treatment can be done according to the cause..
In case of dental abscess,
root canal treatment of tooth followed by antibiotics and painkillers will help..
In case of gum infection deep scaling, curettage and followed by antibiotics, painkillers and topical application of gum paint can help..
Do warm saline gargles..
As of now you can apply numbing gel over the painful area and also take anti inflammatory painkiller like
Ibuprofen.
Do antiseptic mouthwash gargles..
Hope this information helps..
Thanks and regards.
Dr.Honey Nandwani Arora.