This is a free hair curves generator for eyelashes. You can download it as an asset bundle and use as a node group or geometry nodes modifier in your project.

Usage

The Generate Eyelashes node group expects a curves object as geometry input. So you need to create curves object with a Surface and UV Map set up. Easiest way to do it is to select the surface object and choose Curve -> Empty Hair in Add menu (Shift + A).

Then you can add Generate Eyelashes as a geometry nodes modifier (or as a node group). Unfortunately you need to set your surface object and UV map again here.

Most of the parameters (like Hair Material) should be self-explanatory. So I won't try to describe every single one here.

For upper and lower eyelids I've tried to set sane defaults. Layer count and layer separation refers to the stacking of eyelashes. The layers are illustrated in the image below, eyelash strands are then instantiated on these curves.

For guide (Upper Eyelid Guide & Lower Eyelid Guide) inputs you can use curves or (subdivided) meshes. It would work better if these are shrinkwrapped to the surface object.

The curve direction seems to matter, if your eyelashes are generated on the inside you can reverse the curve direction. If you use curves and mirror modifier, your curve direction in the mirrored side will be reversed. The node group tries to fix this using the global +X. Please let me know if you find issues related to this.

Needless to say you need to apply the modifier to be able to sculpt the eyelashes. If you don't need sculpting you can keep adding other hair modifiers to modify non-destructively.