A bald head reflects light differently from hair-covered skin. Natural oils, sweat and product residue can all contribute to a glossy look.
Rich moisturisers designed for facial dryness may leave a visible sheen on the scalp. That does not mean your skin is unhealthy — it often means the product was not designed for this area.
Many head shavers want a natural, matte appearance. That is a legitimate finish goal — and one reason scalp-specific textures matter.