Hair and Nails

Using black dye

Q: Because of the colour not catching the hair, is it permissible for a person to dye the hair black and later on (few hours later) go over the black dye with another colour?

Using beard growing oil

Q: My question is regarding beard transplantation. I’m almost 26, I don’t have a beard on my face, just a little under my chin. I have desire to grow a beard and In Sha Allah grow a healthy beard according to the sunnah in the next few years. Is it allowed to go for a beard transplantation or use any beard growing oil on face? Will it be against the creation of Allah?