If you decide to re-dye your gray chevelure after two weeks, you should know how to treat it properly. This way, you will not only prepare your hair for absorbing a new color but help your locks restore. I advise the following caring techniques between the coloring sessions:
use a high-quality shampoo and conditioner with moisturizing or nourishing properties;
avoid using heat styling tools, and if you do, use heat protection first;
apply a deeply nourishing mask to your locks once a week and let it sit for 20 minutes;
protect your hair from harmful UV rays by wearing a hat or other hair accessories (it can cause yellowish tones too).