Any and all adhesive residue should be removed with a sponge and warm water, then any damage can be repaired easily by skim-coating the surface with joint compound. Use a ten or twelve inch drywall finishers knife (trowel) to spread the skimcoat. Once dried the skimcoat can easily be sanded with drywall sanding paper. Next paint on primer and then paint on finish. Nothin to it!