I’ve been dying my hair brown with L’Oréal casting semi permanent dye for about 10 years and I’ve noticed that over time it’s become patchy. It’s always in the same areas of my hair - some become very dark almost black and other areas are lighter. I really take my time to ensure it’s even and I follow the packet instructions, but still this happens. I’ve tried dying it darker and also leaving it longer to try to reset it but it still happens in the same places. I have read that some areas of the hair are just more porous than others, so wondering if anyone who has knowledge could tell me if I can I actually do anything about this? Or would be hairdresser be able to? I’m worried it’s a lost cause and I’m destined to have bad hair forever! Thank you