At the risk of sounding like your mum, quit smoking now! Unless you're a tobacco company, no good has ever come of this habit.
I was going to suggest that your mum take you to the doctor ASAP--I'm happy that she's beaten me to the punch. You might want to take with you any questions you might have. Anything unexplained sore is scary, and if it hasn't cleared up in just a few weeks, it really ought to be checked out. It's unlikely that you have tongue cancer, but I'm glad that you're being proactive.
As wonderful as the internet is, it's really not meant to be a diagnostic tool; this is especially true when you're already scared out of your shorts. Worst case scenarios seem to be the web's stock in trade.
Let us know how it turns out.