that's a good (and very reasonable) question. i suggest you call your surgeon's office and ask the nurse or pa. generally whenever someone has scalp incisions we recommend they wait until the incisions are fully healed staples/sutures removed and so on before they apply any hair color. you want to make sure you don't have any openings in the skin when you apply the colorant because this could be irritating or lead to infection. so again best bet is to call your surgeon's office and ask. they can give you specific information. glad to hear you survived the brain aneurysm!
how soon can i safely color my hair after surgery for a brain aneurysm?