How bad a dent are you talking about? Small dents, medium dents or large dents you need to tell us or show a pic.of the damage
There are several ways to fix them by welding a stud or drilling a hole and using a slide hammer on the two or shrinking them if they are not to big with heat and a damp cloth,leading them if not to big etc. or cut out a piece as a last resort and weld in a new piece.
62Blue
Don