There's only so much magic a fairy can do. The good fairies weren't powerful enough to force Maleficent to remove it or change it any further.

To be extra safe, the good fairies took Aurora with them into the forest to raise her. The King, meanwhile, ordered all the spinning needles to be destroyed. Years passed, and Maleficent was angry that the princess couldn't be found. The princess grew up not knowing about her royal family, and became beautiful and kind, always playing in the forest with her animal friends. The day before her sixteenth birthday, a wandering prince - the very same she was engaged to as a baby! - found her, and they fell in love. When she returned home to tell the fairies her good news, they revealed she was a princess