If you're going to do postwork in Photoshop anyway, I wouldn't worry with forcing it to work via shaders. The way lhiannan said will do just fine. select the white of the blade (I used the magic wand at tolerance 16), copy, paste as a new layer. use the outer glow layer style, use a bright red that's close the existing glow on the sabre (like RGB 255, 69,60). I used Blend Mode normal, spread 15%, size 60%, opacity 100%. The Blend Modes of overlay and soft light might give good results too. You could also flatten the glow layer and blur it a bit to soften up the blade.

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