How can i treat a gunshot wound at home?

Poorly!: Any gun shot wound requires evaluation by a physician. Even through-and-through GSW's can injure adjacent nerves, blood vessels and organs due to the "blast effect." This is the shock wave that moves ahead of the bullet through the tissue like a violent form of the ripples that spread outward from a rock thrown into a pond. There will never be an easier time to get treated than immediately!

After hospital ???: After you've already been evaluated?? Or in lieu of being evaluated. ?? Unless it is a graze wound you should be seen by a surgeon to ensure there is no occult injury. Then focus on keeping the wound clean etc. if pain is increasing or increased bleeding /idscharge or if high fevers. Get to ER.