Yes, permed hair can be temporarily straightened with a flat iron or permanently straightened with a relaxer or straight-perm application. In most cases, a chemical relaxer is inappropriately harsh as the hair is already damaged from the initial perm. Gentle acid perms are used to remove or straighten a perm.
To straighten permed hair, a stylist combs regular perm solution through the hair. This permanently alters the shape of the hair, rendering it sleek and straight. Because perm solution causes chemical damage, the stylist often performs a deep-conditioning treatment afterwards to restore the condition of the hair and prevent the appearance of frizz.