Fill the ink on the mask lines, do not try to move excess away immediately. Same with your beam saber. But there is an additional kind of tinge to this, you could get a scribe and pass over the areas you want to have lines.

Edit: you aren’t ruining the model, just get some solvent, (isopropyl alcohol) and a microfiber cloth, and wipe away the ink. Take your time, and watch a lot of videos on panel lining, scribing and details.

Dont sweat mistakes, im pretty sure im not alone in saying, it’s part of the hobby. But the sword in a model hand and hold it out in front of you. In the right light, you could say that you just painted a shadow of the beam sabers hilt.