Open the rendering that you want to edit in photoshop and make a copy of the layer.
On the upper layer, select the bright areas that you want to apply the glow on, using the magnetic lasso or the polygonal lasso tool. (Alternatively you could render an alpha channel for that specific part of the object so that you don’t need to select anything afterwards).
After having selected all the needed parts, chose a large brush with white color and paint the selected area