Try alcohol, I used it on my uniforms all the time and it worked really well, even after eight to twelve hours of work.
I've had the best luck with repeatedly spaying with hair spray (for control) or just pour alcohol over area and blot. Repeat several times, then saturate well with alcohol, Spray and Wash and liquid laundry detergent. Rub vigorously and immediately put in the wash. May have to repeat. DO NOT put in the dryer until satisfied with results. I get ink stains from pens and markers in nursing uniforms all the time. Good luck
Use toothpaste mixed with baking soda. Mix one part baking soda with one part toothpaste. Apply this mixture directly to the marker stain and let it sit for a moment or two. Take a clean, slightly dampened cloth and use this to rub the mixture into the stain using circular motions. This may take a little elbow grease, but the stain should come off.
Yes, try good old rubbing alcohol. Yes, the ink will run so please put some paper towels under the article and then I always use a little dawn liquid soap to wash the area to,see if the ink has disappeared.