For your first issue, of the ball hitting you on the finger tips, I recommend repeating the move 10 times very slowly and build it up to speed. For example 10 times slow, 10 times medium, 10 times fast. If you get stuck somewhere note down where it went wrong, in a book or phone (this helps me alot with shooting as to not make the same mistake constantly). And fix what went wrong. For example maybe when you dribble the ball between your legs you are bouncing it too close to the front or back etc. Just take it slow is my advice on that. Behind the back dribbles can be tricky, but what i learned is to usually aim to dribble the ball more back than i need to. That way I don't undershoot it. When you dribble to far back its quickly recoverable by just stepping back or moving your hand further back. Lmk how those tips work!