be (all) skin and bone(s)
To be extremely thin. I know the merger has been stressful, but have you been eating? Because you're skin and bone these days. I was all skin and bones after I returned from my service trip, so my mom insisted on making me home-cooked meals for a month.
be skin and bone
be very thin.be (all/just/nothing but) skin and ˈbone(s)
(informal) be very or too thin: After two years in prison, he was nothing but skin and bone.