How to add a highlight to the lower lip?

[nizhuan-jjr]

The exported files from KKBP do not have an image for the lip highlight, which is also not addressed in Blender shader nodes. This is what the game looks. There's no option for adding/tuning the lip highlight. I have no idea how to extract the lip highlight from the Material Editor of the Koikatsu, either. Face Detail Mask has a transparent area for the lip highlight, so...I'm lost here.

[nizhuan-jjr]

By the way, the lipstick really doesn't blend the same as the game. This is what the result from default nodes. I changed a node from Multiply to Mix. This gives a better result, though I feel the blurness is not the same as the game.