If you're this anxious about it, that might be what's distracting you in the first place. Just go back if you want to and don't if you don't. It's easy to miss things even if you catch every word in some books, just like a movie or TV show. Don't sweat it, just enjoy it. It's for you and no one else.

If you want to go back and re-read some sections because other people pointed out things you may have missed, go for it. That's all perfectly normal.