You'd be looking for a screen protector, rather than a case. At least for your face protection needs. Zagg Glass is what some people have been using for screen protection. Since it's glass, that is what would crack instead of your iPhone screen. Unless a large amount of pressure is applied to one spot.
Plus, since it's tempered glass, it won't shatter. Only crack and spider. Not shatter into a bunch of pieces.
If you don't want glass, then Zagg HDX is also another popular amongst MR forums. Spigen also makes a glass and non-glass screen protector, but I've read some reviews that aren't so great about it. Although the same can be said for Zagg.
If you're needing a case with a built in screen protector, look at Otterbox, Lifeproof, iBlason, and Supcase, just to name a few.