| br>I don't know of a "PCB mask pen" - do you mean PCB resist pen, such as would be used to hand-draw a board before etching it? If so, I doubt that will be very helpful because it's designed to resist etching chemicals, not heat.
As CLee said, you probably don't need to repair this. Just be careful not to create solder bridges that short out your power supply when you re-do the soldering. If that is what it looks like, a Eurorack power header, then the centre six pins are all meant to be shorted together anyway, as are the pairs of pins at either end, so as long as you don't create a solder bridge between those groups, you don't need to worry about bridges within a group.
I have occasionally fixed up tiny scratches in a solder mask using a same-colour Sharpie marker, but that's just for cosmetic purposes. Nail polish might also be worth a try. But neither will really hold up to soldering heat. br> br>