It is a fairly simple process to fix it properly but if you are not familiar with glass work you should be able to hire a pro to do it for not much money.
I had a large ( 3")through hull discharge that I removed last spring. As has been said above you need to grind on the outside back about 2 inches all around to allow new glass work. I had a pro do the actual glass work for $50 and it is as good as new. He will glass both sides so you need to grind off a section of interior
paint, and of course have decent access.
Gary