I got the same thing a few months ago. It was a pea sized lump in the middle of my tongue which would get larger and smaller daily.
I have been using chewing tobacco daily for about 20 years.
I have just had a biopsy, and will get the results in a day or two. I'm glad to hear a few of these instances haven't been cancer so far. Also, my doctor mentioned it didn't look cancerous and maybe more like scar tissue.