I've painted the inside of a medicine cabinet before (super fun!), but lining it with paper or fabric is a great idea! (And makes it easier when it comes time to move from your rental.) My bathroom cabinet
Chair with basket of towels . Lovely pink bathroom with pale pink walls paint color, chair rail & beadboard, glossy white pedestal sinks, white medicine cabinets, marble mosaic square tiles floor and herringbone bath mats.