my car got egged before and I only had it only for a week! i know your pain man!

 

ah yes...the shelll will chip the paint, must touch up or repaint...(touch up wont look great)
egg, bird poo, tree sap, bologna, hard water etc, will eat paint. Its the acids in some or the mineral deposits (magnesium, calcium etc) that do the damage. Nothing is going to protect it...you could get something to go over it, but then the stuff would eat that and you would have to remove or recondition it just like paint...its a labor of love...

 

it sucks but what goes around, comes around and they will get theirs