Style & Wet Newly Permed Hair
A: The reason for the recommended wait time between getting a chemical service such as a perm and shampooing the hair is to allow the hair time to "normalize" and fully adjust to the new wave patterns before doing anything that can affect the wave pattern.
You know that perms work to add curl by breaking the chemical side bonds in the hair and reforming them in the shape of the tools used to wrap the hair. When properly done, the neutralizing step in the perm process reforms the chemical bonds, leaving them completely stable.
The reason it is recommended that you not shampoo or wet the hair for a certain period of time afterward is because water will break both sets of physical side bonds and leave the hair fully reliant on the newly reformed chemical bonds for elasticity and curl.
The 48-hour recommended wait time is to allow the hair to fully re-stabilize, thus ensuring the best and longest-lasting results from your perm. Wetting the hair, or even shampooing the hair, earlier than recommended may not have any negative effect in your case.
However, there is no guarantee that the bonds won't be affected, and since there's no way to test the bonds apart from the visual check of the curls created, clients are encouraged to give a reasonable amount of time before resuming their normal routine.
If you need to "style" the hair on the days between perming and the end of the 48-hour waiting period, you can use light styling products sparingly to refresh the style. Just use good judgment and don't subject your hair to any harsh styling procedures.
©Hairfinder.com
See also:
Perms and perming hair
How soon following a perm can one get hair wet in a spa tub?
How long after getting a perm do I have to wait to swim in a pool?