The time it takes for your hair (and nails) to grow is a biological process that can't be sped up or slowed down as it takes place in your hair follicles under your skin. No spell, or herbal remedy for that matter, will speed this natural process up. But herbal remedies can make your hair smoother, softer, and shinier by soothing the platelettes, but it won't make it grow faster.
Magic can't change your physical appearance in any way, that's just not how it works. If you're truly interested in learning about the craft, I would do some research about what magic is and isn't.
if you believe in the law of attraction, you can listen to appearance changing subliminals. Affirmations work as well. Ex; if you want longer hair: My hair is so long and healthy.
When I incorporate this into my spell work I will get a pink or red candle (cleanse it) and charge it with my intentions. Sometimes I will carve my intentions into the candle. Then I take a piece of paper, write my intentions, meditate on it. After that I light the candle and let the universe do it's work. I do a lot of beauty spells this way.
If your going to do subliminals I would record my own because you never know what person who recorded it intentions are.