Correct. Consider a new helmet, even if it's a cheaper model from the same maker or some other brand that Nashbar or somebody else is blowing out for $90. They're not that hard to find. The means to ascertain whether a helmet is 'OK' after a crash is well beyond any local bike shop. Think Xrays, engineering analysis, etc. The helmet could look fine but it may not be and it may not properly absorb impact in the next crash.

Err on the side of caution in this case. Something to think about. While you still can I mean.