A sleeping mask is basically a richer night moisturiser. So rich that not all the product will be absorbed into the skin when you wake up the next day. They always tell you to wipe off or wash off in the morning.
This is not bad. I like that it is just a sample size but you can use this for like 3 days. It is a clear gel very much like the moisturiser. But it is slightly richer. There is not much different in term of consistency. I just would not use this in the morning. Cause it is not for oily skin. Maybe it is the problem with the range and not the product.
Anyway, my skin did not lighten but it sure is moisturised.