try also different layer modes and gradients

Using your template - Fuzzy selected then inverted the transparent area to just select the nail. I took the red back to white. Added a transparent layer and with a black to white gradient did a linear stroke across the nail at the widest place. Taking the gradient out as far as possible or to your satisfaction.

I then copied it a couple times using multiply layer mode. I blurred the bottom layer before applying lighting effects - bump map.

If you haven't already merged your layers, copy one of the black and white layers and put at the bottom of the layer stack. Now you can safely merge them all and use colorise to get the colour you want or use another gradient.

Last of all add some contrast and that will make your white stand out more.

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