You might want to call the company that makes the pen and ask them what they recommend. My choice of product is Spot Shot in the aerosol can.

Here is a link that might be useful: Spot Shot

I was able to get red and purple kool-aid or marker out of my carpet with Oxiclean. I'm not sure which it was because it was on the carpet when we bought the house.

Hair spray.
The NON-aerosol type.
My son colored our brand new trucks cloth interior with black permanent marker and I had it spotless before his Dad got home. :)

OOPS~I meant the aerosol type.
(The one that you can push the button and it keeps spraying.)
I used RAVE by the way if that helps at all.

Straight alcohol.

Winning Colours stain remover may work. I used it for two year old paint stain on my carpet and it took it right out! The link is below.

Here is a link that might be useful: Carpet stain remover - Winning Colours