How do I cover my few greys permanently?

I have a few greys in my hairline and on the crown, an ex hairdresser recommended that i use clairol perfect 10 and I did do. It claims to permanently cover greys till they grow out. However Ive found that my greys are already showing again after about 2 weeks. So thats more like a semi permanent tint. Does anyone have any suggestions as to why it hasnt permanently coloured the greys? I leave it on for 10 minutes like it says to on the packet.

skin lesions

debt