Question 1: You need to consult with your doctor for medical advice. Question 2: How to save color for future applications. Whatever color you do not mix with developer may be saved for the following month's application or stored for up to a year. Once you mix color and developer, you must use it immediately. For coloring grays, mix equal parts color to developer and apply this full strength mixture to roots only. Process the roots for 25-30 minutes, or if you have resistant gray 30-45 minutes. You need to shampoo and condition the color out.
