Had the exact same problem with very light tan leather when I left a standard ball point ink pen on the seat of my wife's brand new Subaru during a very hot New England day.
Tried everything, nothing worked, spotted the can of bug and tar remover and figured that I could not be in any more trouble so what the heck-every trace of ink came out.
As I recall I first dabbed a bit on the large mark and let it sit for a few seconds then blotted it out, repeated and waited a few seconds longer then when I felt comfortable that none of the dye was going to be removed I put more on, let it sit for about thirty seconds and rubbed with great vigor. Finished by wipping with a mild soap solution.
This was doing the summer so the seat was very warm, not sure if this is important or not-I wish you good luck.