From childhood (I can still see the little "frame" in the comic book), I recall that one way of capturing a mustang/wild horse in order to tame it - according to Western comics and feature films, that is - was to shoot the poor crittur through the neck in order to stun it, and I'm sure this was called "creasing". I think RM Ballantyne also refers to this practice in "The Dog Crusoe".

Don't know how similar you'll find the expression, Virginia Tam, but in Glasgow there's an expression referring to making some cranial alterations: one characteristically abrasive threat is to "sherpin' yer heid", presumably by grinding it along the ground. In Scots, what you've referred to as a "dent" would be a "dinge" (soft "G"), while the similar-sounding "dunt" is actually a bump, blow, strike, hit &c. And "critter"/"crittur" might be derived more immediately from Irish "cratur" (often given in writing as "craythur", to mimic one pronunciation), which is generally used in a rather gently regretful way, often in phrase, "ah, the poor cratur".   

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