Title says it all, is there a way to allow block damage and stop healing in a worldguard region when creeperheal is enabled for that world?

Ah, sorry, no, that's not possible currently. I don't interact directly with WG.

No, I want to have a worldguard region that allows block damage from explosions and creeper heal to not heal the damage.

erm... I'm not exactly sure what you mean. But you can disable WG's handling of explosions, and let CH do its job instead, is that what you're looking for?