Squished My Cats Tail

Question
We have a concrete floor and I leaned back in my wooden chair and squished my cats tail.  As soon as I heard the yelp I leaned forward and he ran away scared of me and hid.

Half of his tail hangs limp. My roommate and I don't think we feel a kink. He pulls the tail back when I run my finger down it making an arch the whole way, but doesn't pull it back when I slide my fingers straight down it. Either way he never yells about it. And he seems to have totally lost sensation in the second half of his tail.

What do you think is wrong?  Broken?  Can we handle it with out going to a vet?  Do you think he'll recover on his own?  How long do you think it'll take?

Answer
If you leave it alone, most likely it will either
1) heal and restore completely
2) continue to be limp with no feeling, which can hinder your cats' balance

If you take him to the vet, they will be able to most likely restore it.

There's no way I could guess or tell how long without me personally seeing him....but a call to a vet couldn't hurt, and you could describe what's going on. =]