Painting over Cerakote

Key the surface/rub back with 600 followed by 800 grit wet and dry. This will key the surface yet be smooth enough to allow for a good finish with your chosen paint

Eventually you will endure some chipping/show through but with some patience you could work back most of the cerekote
 
Nothing sticks to cerakote (that has fully cured) very well, even another coating of cerakote. This is why multi-color cerakote paint jobs (heat cure) are shot with a partial cure and secondary colors applied before full heat curing is done. Air cure multi color jobs are done with stencils and selective abrasive blasting to prep surfaces for each color.

I've got one rifle I base coated with OD green and have painted different stripe patterns on with enamel paints. Enamels will spray on pretty good but will scratch off fairly easily but the basecoat cerakote is usually just fine with no damage unless it was a pretty good gouge or deep scratch into the surface. When I want to try a new pattern I just dig out some acetone and literally wipe it off with some time and effort.