Looking to have black edges cleaned up. Are all lasers created equally in terms of precision? (photos)

I have a few very small areas of blowouts surrounding a very largetattoo. I'm basically just looking to have some black edges cleaned up. Three questions. Are all lasers created equally in terms of precision? I read somewhere they apply white ink over the areas you don't want removed. Does this work? Finally, how long do I have to wait? I just had it done a week ago, but it's unsightly and not helping my first tattoo regret.