Im a 30 year old woman with a history of chronic sinus infection.  A few months ago I suffered a very bad bout of infection - it was so bad that my left cheek became tender and swollen.  After two courses of antibiotics it had cleared enough to reduce the swelling, but I didnt realise that it hadnt cleared completely.  Ive noticed that my face is still slightly swollen on the left and today I noticed that its very tender and a small, soft (apparently liquid filled) lump has appeared high on my gum line slightly behind my upper left canine.  Would this be related to the sinus infection?  I have a very high pain threshold and havent noticed anything other than pressure and tenderness in the affected area.
Your swelling may be due to two reasons.1. Dental abscess that is formation of pus deep to the root of a tooth. sometimes this may be painful or may be pain less.2. Chronic sinusitis leading to accumulation of pus in the maxillary sinus. I suggest you to consult a ENT specialist and take advise regarding sinusitis. An X-ray may reveal the source. And a small surgery may be necessary. If there is no fluid there in sinus, consult Dentist for opinion about Dental access.