the lump in your mouth sounds like an ulcer. I have a lump on the middle top of my tongue and cant stop worrying because it's painless. the internet is scaring me. but the red ring you mentioned is the sign of ulcer. Not serious.
I too have had the exact same thing. I am a 20 year old, heavy smoker, on about 20 a day since I was 13. Ive recently been very worried about my health orally, as I have experienced pains in my mouth. I have a very small lump in my chin/jaw line, its completely painless, soft, and I can move it around, I have come up in very large, yellow headed spots behind my ears, and on my neck, and just about a month ago, noticed I had a small, hard, white lump in the back of the roof of my mouth on the left hand side. Its not painful, but Im worried about it as when I shone a light in my mouth it appeared raised, white, and had a red ring around it. I have no idea how to deal with this, and its been causing me sleepless nights, worrying its oral cancer. Im seeing a doctor in a month and I will explain this all to him...but for now can someone please give me some peace of mind?!
Seeing a dentist is advised.