How do I do this?

So yesterday, I took leap of faith and tried myself at some home beauty, and more specifically at coloring my own hair to get rid of those stupid white hairs that decided to grow right exactly where I part my hair, at the place where you’re the most likely to see them. Damn…

So ok, I know it’s only the second time I’ve colored my hair at home, so I knew I wouldn’t be a pro. So I followed the instructions on the box suuuuuuper carefully. The color seems to have worked everywhere…

Except on my $&@#%%¥ white hair!

Guys, do you know what’s the problem? Is it the time I left it in? Is the color not strong enough? Whaaaat? Help!

PS I used L’Oréal Healthy Look Créme Color Gloss.