It might be helpful for you Anita... https://www.youtube.com/watch?v=eBruRStXYAY
Hi Anita: Try one of those magic erasers. But, alas, the marker may have permeated the hair and stained it for good. If that's the case, just look at it as a new trend in hair colouring) Good luck
Lots of marker is removed with alcohol or hairspray.
This will help: https://www.wikihow.com/Clean-Marker-off-a-Doll
try hairspry! the alcohol in the hairspray removes ink!