The Department of State advises:
If your passport has been significantly damaged, especially the book cover or the page displaying your personal data and photo, you will need to apply for a new passport. Conditions that may constitute damage requiring you to replace your passport include water damage, a significant tear, unofficial markings on the data page, missing visa pages (torn out), a hole punch, or other injuries.
Normal wear of a U.S. passport is expected and likely does not constitute "damage." For instance normal wear includes the bend of a passport after being carried in your back pocket or fanning of the visa pages after extensive opening and closing.
"other injuries" is vague but with nothing missing or illegible I think you should be "OK".