Hi, I would like to start using cp serum or protect and restore cream again. I have both and they are about 4 years old. I have a small amount of each. Would it still be okay to use or is it too old? I have some redness I think so I want to be carful. I plan on ordering more soon, but I want to make sure my skin isn't too sensitive to it before I order more. I just want to make sure I can still use it on my skin.