"Sheasa nisim" after doing the mitzva

Question

Shulchan Aruch, OC 692, says that if someone reads m'gilas Ester without reciting the benedictions before and after it then he fulfills his obligation of reading Ester. It doesn't say what to do about the benedictions, however. I wonder about "sheasa nisim". Is there some way to say it after the fact?

Someone who cannot light Chanuka lights says "sheasa nisim" if he sees someone else's lights. What if he already satisfied his lighting requirement, but skipped saying that benediction? Is there some way to say it after the fact?

Answer 1

Kaf HaChaim 692:1:3 says in the name of the Mahari Molcho that one can only say Sheas Nisim on the Megila.

Mishna Berura 692:3 one can make the Bracha even a second time if they are reading the Megila for someone else. So I think a potential solution for one who forgot the Bracha is to read the Megila for someone else or to listen to the Bracha of one who is reading after them and be included.