Please help.

I have two very large key scratches on my car and have attempted to fix them using a paint pen set.  I followed the instructions to the letter but unfortunatley they didn't tell me to ensure the paint only went into the scratch so now I have a raised surface on my car around the scratch.  I tried sanding this but the surface around the scratch dulls and the primer still doesn't sand flat.

How can I get the primer to be level with the existing paint without damaging the paintwork further?

:'(

You want to use rubbing compound as this will not dull the paint. By gradually bring down the new paint, you will make it level with the existing surface. Did you try a small section first? If not, get some automotive lacquer thinner, remove the paint and try fixing just a very small section of the scratch until you have the technique down. You don't want to use sandpaper as this will mar the existing finish.