Can I say "hell" instead of "heck" here? What's the difference?
Yes, you could replace "heck" with "hell" here and it would have the same overall meaning. "Heck" and "hell" pretty much mean the same thing, except "heck" is a little less of a swear word than "hell" and it is often used in place of "hell". If you used "hell" here, it would sound stronger and more like you are swearing. Children often use "heck" because it sounds nicer and is not really swearing. Ex: What the heck happened to your face? Ex: What the hell happened to your face? In the examples above, "heck" and "hell" both express surprise, but "heck" sounds a little more silly and mild, whereas "hell" is stronger and indicates a little bit of anger.