Your cosmetics 3D model is dark in Blender mainly due to insufficient scene lighting, incorrect material settings, or the viewport being in a non-light-preview mode (like Solid instead of Material Preview).
Insufficient lighting means you haven’t added enough lights (e.g., Area or Point lights) to illuminate the model. Material issues could be a too-dark base color or high roughness (reducing surface reflectivity). Solid mode only shows flat colors, not how materials interact with light.
If it’s still dark, check for flipped normals (faces facing inward)—go to Edit Mode, select all, and use Blender’s “Recalculate Normals” tool to fix it.