Thank you for your reply. My hair has never been able to withstand permanent waves or coloring without breaking or dissolving my hair, mostly at the hairline. I made a big mistake this time because of the henna, I understand. Although the henna did not break my hair, the gray didn't cover and I couldn't stand it anymore. Would you be able to tell me how long I should wait before using your coloring again? Also, how long in between coloring and then touching up gray with your coloring? Thank you so much.