Dry ice is not a solution, just a trick that can sometimes be used for some damage--not a typical practice, just something that works when it works. Takes a while, and doesn't leave a 100% perfect result a lot of the time, so people play with that usually if they have one big dent...and not 15 of them all over.
If the dents aren't bad, and if there aren't 1000,etc., a paintless dent removal service might be able to do it--all depending, again, on the location, if they're near/on seams and folds in the sheetmetal, etc.
For pieces that can't be "un-dented", panel replacement is the next step.
As odd as it may sound...quite often there will be brand new vehicles straight off dealer lots (almost always from the southwest) that are written off/totaled after hail damage causing a load of small dents. Essentially, rather than pay to replace panels and all the time & aggravation of removing them, insurance will just write them off.
NOT that it's something that would also happen after damage in your driveway (that should be fixed using one of the methods discussed, after someone decides/pays), but it does happen.