Please go get it checked out by an ENT or oral surgeon. You will worry about it until you get an answer, waiting doesn't do you any good. I have had two biopsies on my tongue, they were not too painful, it bled some but no stitches were necessary, it will heal quickly. I don't think mine was particularly hard but was a sore that wouldn't heal and was definitely white. Good luck and hopefully it's not cancer! If it is come on back and everyone will give you support and advice.