Some helmets are rated for multiple impacts and some are not. Generally if the foam of your helmet looks like styrofoam, it's probably a "crush" design. The foam crushes on the impact to absorb energy. That is a one and done helmet. If the foam is crushed it's done. One and done helmets tend to be a lot lighter.
Others like many protec models are multiple impact rated. So you bounce your head off of a groomer and it's probably fine to do again. Opposite of the crush helmets a multiple impact helmet tends to be a heavier design. Noticably heavier.
No matter what helmet you use, if it takes a major impact that helmet should be retired. The multiple use ones can only take so much. If you take a hard impact and wake up down at ski patrol, it's probably time to get a new helmet.
So what helmet were you sporting?