Wait to wash your hair for at least 24 hours after you get a perm. During the first 24 hours, your hair is getting accustomed to the chemicals. It is also abundantly fragile during this time.
If you wish to take a shower during the first 24-hour period after receiving a perm, go ahead and wet it down if you feel you need to. However, do not apply any shampoo, conditioner or other products. It is best to allow your hair to air dry during this time. After you have waited the appropriate amount of time, use shampoos and conditioners that are specifically created for chemically treated hair.