How to fix wall damage from feeling off the wall paper before painting?

I am taking off the old wall paper (10yrs old), no liquid apply, some area has been damaged by the old glue with fast peeling, use the sander to get rid of the glue. I put new sheetrock to repair, then, texture it, paint it, it still shows the damage and the repair lines. Anyone knows what is the best way to repair wall damage and without leave a mark? Need a Quick and effective solution. Thanks.