i have a red spot on my tongue and my fuz / small taste buds r missing from there

the other day it felt like i had a terible kanka sore but it also felt like it was comeing from the back of my mouth then when i looked i saw i had a red spot on my tongue that was missing the fuz / small taste buds bud now its spreading that erea what is it if some one can tell me i would greatly appreciate it thanx joe