I’ve just purchased a touch up pen for the same job. Any advice on the polishing/finishing stage?
I didn’t use a pen ( I used paint and tiny brushes to almost drop the paint in) but I guess the principles are the same.
I built the chips up in layers, allowing each to cure for a day or two to allow for sink back, until the level was just proud.
I then wet sanded (by hand) them down to be flat and essentially level and invisible with the adjacent paint.
I think I went sequentially from 1200- 1500 - 2000-2500-3000 grits. Each time you have to go out a little further than the last.
You can buy really small (1”) discs in those grades off Amazon (come as an assortment) and a little holder that the velcro on to:
Search “25mm cylindrical sanding block” and “180 pcs 1 (25mm) sanding discs hook and loop”
But, I ended up doing most of the sanding by hand with just small pieces of wet and dry because all though it’s slower, you have more control.
To finish, I polished using Menzerna ‘Cut Force Pro’ just on a small pad running on my electric drill….set as SLOW as it would possibly go…as it’s the smallest thing I have. You can’t get those really small head polishers but I don’t have one.
It just takes a very long time. Doing it al under a really bright light. Hope that helps.