root lift perm

Ok I have fine hair and a round face.  My hair is sholder length and I can't stand having short hair.  I have been recommended that I need to create volume on the crown and very little volume on the sides to create a thinner look, so I don't want extensions.  I have heard of a root lift perm.  Does that do as much damage to fine hair?  Has anyone tried this?  How long does it last?  Also I can get my hair to have body it is just keeping that body for more than 5 minutes.  Of all the styling products I use, a couple of days later my scalp starts itching like crazy.  (allergic reaction?). Help