Tails!

Hi everyone just a quick question for anyone who has a boxer/dobe or those kind of breeds with tails. My little girl (boxer) caught the end of hers whilst wagging it so much at my mums and hit it on the radiator (ouch!) which then made it bleed so now we have to be careful around kitchen doors etc. One of our Mals had the same prob but as he hasnt hit it for a few years it seems to of hardend up a lot. If anyone has had the same prob i would like some advice please?