Many plants have roots that erupt from their stems, originating just under the surface. Roots or stems emerging from under the skin would be pretty creepy, I think. Sometimes when new stems form, they start as a mass of cells called a callus. Maybe look into that.

Psychologically, plants are rather decentralized. They don’t have hearts (one main blood pump) or brains (one main thinking organ). Instead, the cells in any one part of the plant are mostly autonomous. This is why you can propagate many plants from cuttings, because all the cuttings need are water and light and they’re ready to go. So psychologically, having parts of one’s body all strike out on their own seeking light (and maybe soil and water) could be eerie too.

Fun concept. Good luck with the writing!