I was thinking that too - a wicked case of thrush or some other infection. The one thing that concerns me is the area under your tongue you say is hardened. What does it look like?

Honestly skip the oral surgeon ask for a referral to an ENT, and then call them personally to ask for any kind of cancellation placement. Don't take this to mean I personally think its cancer, i don't... but realistically speaking this is worrying you and whatever it is needs to be treated. Best of luck.