I don't have dry skin, but I do find that the green clay is a bit drying, even with use of the Da Vinci Water. I have the MaleFace moisturizer that I apply after the Green Clay. It works really well. BTW Charles does recommend that people use something after the clay treatment to moisturize the skin.
Maybe you should also look into changing your face wash. Something that is more mild and moisturizes. Maybe an olive oil soap, or a soap with shea butter. I use Papoutsanis olive oil soap and find it fantastic (and cheap too at $1.35 for a 250gr. bar).
No, in all these things we are more than conquerors through him who loved us. For I am sure that neither death, nor life, nor angels, nor principalities, nor things present, nor things to come, not powers, nor height, nor depth, nor anything else in creation, will be able to separate us from the love of God in Christ Jesus our Lord - Romans 8:37-39