Only repaired a car similarly damaged like this about 2 weeks ago.
Depending on the paint that was thrown over it you might have an easy fix on your hands.
If its (water based) emulsion ,,,,,,fairly hot water, (not boiled) a little elbow grease and a machine compound and glaze should as good as sort it.
If its gloss paint then its a different story.
Best option would be to try some standard base coat thinners. Make sure you have a good look at each panel to see if they are originally painted before you start wiping it on. You don't want to be putting it on aftermarket paintwork. Good chance the thinner would damage or stain that.
It is a slow process and it can be soul destroying work but if it can polish off and keep your original paintwork then its worth it