I agree with Davi -- the rest of the sentence is based on the subject "us" being plural, so "selves" works better than "self".!

Yes, this sentence is ok, just a question that came to my mind. I think on this context the "self" goes to plural "selves", because you are using the possessive pronoun "our", so it would look like this:
"All of us use something as a cover for our true selves when we live in a group of people."