Is it obligatory for a woman who has dyed her hair black, and was unaware [of the prohibition], to re-dye it another color? And is the removal of hair between the eyebrows forbidden?

Dyeing hair black is forbidden for those with gray hair, but permissible for those whose hair is naturally black. Whoever does so knowingly and intentionally must repent and seek forgiveness, and remove the color if it does not cause harm. Whoever did not know, bears no sin, but must remove it. Tattooing is forbidden and is a major sin. If a girl was tattooed when she was young, she bears no sin; the sin is upon the one who did it to her. She must remove it if possible without harm. As for removing hair between the eyebrows, it is permissible because it is not part of them.