You can return to the beautician as soon as all of your wounds are healed and there is no scabbing. You should not color or bleach the hair until all of the wounds are healed. It may be a good idea to have the hair colored shortly before surgery.
Dr. Hudson does not recommend that you have the hair cut just before surgery. Extra length may allow you to conceal the scars more easily. In men this is especially important and some men may need to change their hair style, for example growing sideburns, to hide the incisions.