Shouldn’t be too difficult Angel.
I did a quick example and took a screen grab for you. For ease i have made reference to the layer names in my project/screen grab. For clarity, i have enhanced the effect so that it is more visible but less realistic (turn the opacity down on the additive layers in your version to make it more realistic.)
Duplicate the layer. (GIRL HIGHLIGHT LGE)
Make a small feathered mask for the highlighted area.
Switch the layer mode to add.
Add a colour balance to that and adjust until the colours match
Duplicate GIRL HIGHLIGHT LGE
Reduce the size of the mask to make a smaller, more intense central highlight
Adjust the opacity of both highlight layers until it looks natural
i also made a precomp (SHINE) and masked ares of the original shot to emulate light streaks. in the main comp (SUN HIGHLIGHT MAIN…
make the SHINE layer additive
add shine to it
move the shine source point up and right outside of the image area to crate directional sunlight streaks
that should get you started. a small amount of a lens flare glow, matching the grades etc will also help.

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