Oh man, I'm sooo sorry!!
As the other poster suggested the other day, tape does work to remove light transfer...but you have to be CAREFUL. I'm not sure about pen marks, but I'm about to try one and I'll let you know. Now...I have NO idea about patent leather either, and what this would do....since it's coated, the tape might pull off some of the enamel finish, I'm not sure. Try it lightly. I have used tape on Legacy leather, and it makes it "whitish", and then you just rub and condition it afterward. In fact I just removed a tiny bit on the coin purse of my new sunflower Bridgit...looks like my navy tee bleeds. It worked completely, but it was also fresh bleed, and it wasn't ink. Tape doesn't always work though, and sometimes shipping tape is better than regular tape. Actually someone just gave me a leather bag with a pen mark, and I'm going to try to remove that...it's not a colorfast leather, so I'm not sure what else I can try yet either.
It looks like with the coated surface of patent that it would be easier to remove, though, since it's not so porous (there's a barrier). Magic erasers will sometimes take the color out of leather, but if you try a tiny piece of one very lightly, that might remove the mark. Otherwise, yeah, try all the commercial sources..the erasers, etc. You might ask at a leather shop, and that way you wouldn't have to keep buying stuff to try. They probably have it there. My experience with
Coach is that they are very conservative (I'm sure because of liability reasons), and/or not very knowledgeable in this regard. A good professional can actually even redye if the color is lifted, but I've only experienced suede in this regard. Patent makes it a different situation.
There's also very very dilute bleach (VERY dilute) solution with club soda..supposedly that also will remove marks.
In any event, go lightly and use a Q-tip. Oh, I just saw the above post...is this a perm. marker?? That's going to be tougher, but I've definitely removed perm marker from non leather items with stuff like magic erasers and goo gone too.
Good luck, and again, I'm really sorry this happened to your new bag!!