I had skin cancer (Squamous cell carcinoma) on my scalp, it was removed on the 23rd of June, the hair is just now starting to grow back in. I am 51 years old. I have very long hair, It is gray and dark brown naturally, but before I had the skin cancer I dyed my hair blond so the bottom half is blond. Is there a safe method for dying my hair so I can get it all to one color? Or should I wait a while? Or not do it at all?