I had a filling that fell out never went back to dentist the tooth decayed but now it has a swoollen gum lump inside is this abcessed? No drainage no pain

If there is no pain in or around the tooth, say when you bite on it, or tap it, there should be pain if the tooth is impacted. I would suggest a visit to the dentist to have it extracted if the gum is swollen, then it means trouble. The decay probably started again after the filling fell out.

Hi there, I'm a dental nurse. It sounds like the gum around the tooth is inflamed, it doesn't sound like an acute abscess, but I would advice you to contact a dentist to have it check.
Is the gum swollen on the side of the tooth or does it appear more inside the tooth were the filling use to be? My advice for the short term is rinse your mouth with corsodyl mouthwash, it available from most chemist. I hope this will help you.