If you feel like it, post a sample or two. The photoshop masters here can better advice that way. Not sure how much you can rescue in PP - with fireworks getting the settings right during capture plays a huge role.
You can do the basic staff like adjust curves to enhance constrast, pump up saturation for colors. You can also composite different fireworks photos together. Since the sky is black, setting the layers as Overlay will allow the fireworks to show thru.