To access your photos and comments, go to your profile page, click 'Photos' then select 'My Photos'. Once you're in the My Photos section, you'll be able to view all of your photos, albums, comments and likes.
If you've made comments on other peoples' photos, you'll be able to view them by selecting 'Comments by me'. This will show you all of the comments you've made on other people's photos, in chronological order.
If you'd like to find an older comment you've made, you can search for it by selecting 'Search Photos'. In the search box, enter the name of the person whose photo you commented on, and then enter a keyword or phrase. The search will return any comments you've made on that person's photos.