You are going to get hurt every once in a while whether you practice anything for that matter not just MA. And yeah man pain is scary and it can take a toll on your confidence, but you dont want to let that beat you do you? I mean you dont want to limit yourself as a result of a sprain knee. Look at all the really good fighters out there, the ones that compete today, the ones that competed when you were a child and you were only able to read about them on magazines and what not, a lot of those guys went through far worse than sprain ankles and such. I always try to look at obstacles as blessings, they can only make you a tougher person if you are willing to work your way through and beating them.
When I first started sparring like 2 months into it, a green belt broke my nose. And let me tell you it hurt and it was a shocker because I had never had my nose busted like that before. I seriously at that point considered quitting because it was scary, but I didnt, and not quitting made me a tougher person and neither should you quit doing tornado kicks as a result of an injury. Quitting is always the easy way, there is nothing to gain from quitting, but sticking through it and conquering your fears man thats an accomplishment.