Hi jmg856,
I don't blame you for being concerned considering how the dentist and the nurse reacted and having the biopsy. However, from your picture it looks like you have what they used to call a canker sore. They are lesions in your mouth that are white and can be sore. I had them for years and cured them with lots of Listerine; the original one that tastes strong but kills germs, not the new flavored Listerines. Just rinse your mouth with the original Listerine and "hold" it on the sores. It may sting but it will eventually feel better. I'd also follow through with the biopsy results but in the meantime you may be able to cure them yourself before you see the dentist again.
Good luck!
PML