Since hair is alive, won't damaged hair just grow back?
One of the most common misconceptions about hair is that it is alive, when in fact hair is nonliving and does not heal itself once it is injured. So once the hair is damaged it cannot heal itself except through new hair growth at the scalp.
How about straightening my hair?
If you're straightening hair with a ceramic iron, put a moist towel in the device to protect the hair from direct heat.
There's also a procedure called keratin hair straightening that uses gluteraldehyde or formeldahyde in combination with heat to straighten the hair’s natural bonds. After the chemical solution is applied to the hair, a keratin protein conditioner must be put on the hair to make it less brittle. The hair must be kept dry and not bent or manipulated for several days or the bonds will repair and the hair won't be straight.
Once you do shampoo, use a generous amount of conditioner. If you hair becomes frizzy and brittle anyway, stop the procedure and let new hair grow in.