Is cetaphil facial cleanser could cause serious damage to the body if used frequently for a long time?

No, it's fine to use. Cetaphil facial cleanser or skin cleanser are milder than soaps. The Cetaphil cleansers don't take away too much skin oil, so the cleansers don't leave your skin too dry. These cleansers can be used every day instead of soap. They are not "facial scrubs" or "exfoliators" so won't be abrasive to skin. (Use a little each time, because all cleansers go down the drain, to our water supply or oceans (oxymetazoline).)