The size of  the dish will be critical in answering your questions.

A normal 12-foot  C or KU band dish can sustain a significant amount of damage before it's ability to receive signals is degraded. I don't mean one that looks like Swiss cheese, but a few holes won't make much of a difference. In many cases they can be patched with light aluminum ( not FOIL !) for a solid dish, or a mesh dish with steel screen material.

With the smaller 18" type "DSS" dishes, small dimples won't bother it much, big dents will. No patching here ! However the replacement cost is usually in the $30 to $40 range so it won't be that expensive.

When you have hail - there is usually high winds. If there is a small amount of damage and you still cannot get a reliable - or any - picture, recheck your alignment. That is probably the problem.

We know your smart.... but..... DO NOT MESS WITH THE DISH OR ANY ANTENNA IMMEDIATELY BEFORE, DURING OR IMMEDIATELY AFTER A THUNDER STORM. YOU WILL GET HAMMERED BY LIGHTNING ! If you don't see bright sunlight, stay away from your dish or antenna !