Think about the language we use. Thick-skinned people are perceived as tough and rarely show their emotions. Hard, dry skin expresses that defensiveness on the body. If you struggle to share your true feelings, this may be the root cause of your dry, hardened skin.
The skin may become hardened, dry or form plaques in some conditions. Think of this like armour plating or a defence against the real hurt and sadness inside that has been buried. The armour creates the illusion of strength. To truthfully look at your pain would cause that armour to collapse.
Your emotions exist, even if you rarely show them. It may be time to tear down those walls around your feelings to uncover the link between your emotions and your skin problems.