Been there done that. I had done fiberglass repairs on boats before so it was really no big deal.
How much damage to the corners? YouTube videos should help you understand the process and supplies needed. If it is not to big an area auto repair kits at WalMart if you need more than that try a boating supply to get the cloth and gel coat.
Much like painting its all in the prep. Get a good dust mask or respirator because you will need it.
Lots if sanding and couple of applications and a little paint when your done.
89 2.5 TBI, 4" RC lift, 1" Booms, SYE, Adams Driveshafts front and rear, Ford 8.8 with 4:88s, BFG 33X12.50X15, and a ton of other stuff.
AF Jeep Club Tail Number 184