Taping the fingers CAN help if it's done right, and if the injury is of a character that taping CAN help.

That said... when you've got an injury like that, if you're just in training, I wouldn't push my luck.  I'd give that injury time to heal itself.  That injury doesn't need any more insults.  Treat it with RICE... Rest, Ice, Compression, Elevate, and give that puppy some time to heal.

If you want to continue some sparring training while you let it heal, discuss doing combination work with your instructor that does NOT hazard your injured finger in any way.  This is a great time to work on various combination kicks, on your core body strength, and even do some cardio work to improve your game.  You can also watch sparring critically.  You can learn a lot from watching other people spar... if you see they're making mistakes that are getting them popped, you can check that information against your own game, to see where you can improve your game when you heal up and get back into sparring.

 Hope that finger gets better quickly!