If you're making huge dents in the plastic, you're doing it wrong.
If you're scratching it all up, you're really doing it wrong.
The trick is to push into the plastic clip and then push the whole thing up without twisting the screwdriver. Trying to twist the snaps apart just leads to dents and frustration; you have to unhook the two halves of the snap and they come apart easy.
In my experience it's Dang near impossible to cause significant cosmetic damage with a putty knife, even if you're not being particularly careful.
Do you actually have one of those, epicelite? They're terrible for opening electronics. If you don't already have one, take an orange peeler and try to open something with it. Screwdrivers, putty knives, fingernails, exacto knives > those.