What will happen if the sebaceous gland slows their function?

1.  Someone doing manual labor what would you see when looking at a section of the dermis of their hands?

2.  A callus is a hardening of skin, which protein is very abundant here?

3.  What will happen if the sebaceous gland slows their function?

4.  Why does hair look shinier when we are sweating a lot?

5.  Skin grows from a particular layer, what is the name of this layer and what might happen if this layer gets damaged?