Whenever I start bouncing the yoyo back and forth, I get really nasty friction burns on my non-throw hand index finger. I've tried micropore tape, but it wears through and the net result is the same. I'm not doing it at an odd angle or anything so what am I doing wrong?
You're not doing anything wrong. That's just normal string burn. You get used to it. Alternatively, you can buy a yoyo glove or buy some medical tape. Or just keep going until your hands toughen up. It's up to you.
You can adjust your technique a little if you're good at boing e boing. Try to make the string slide up and down your FH finger slowly as the trick goes so it doesn't rub one spot for too long. Sounds wierd, but a slight tilt of your finger will cause the string to move at just the right speed and prevents string burn.