Boss verbally told me about promotion and raise. I’ve been doing extra duties for a month and just learned I did not get a raise.

Hi all, I work at an after-school program as a tutor. Recently, my boss sent me an email asking me to be the assistant manager at the site. Later in the day, she verbally told me that I would be getting a $3/hr raise. As a result, I started taking over manager duties and had to make long drives for the manager meetings. Last week, I noticed that my paycheck was for the same amount. I reached to my boss only for her to tell me that the promotion didn't go through, except she KNOWS that I am working as a manager because she literally sees me every week for the manager meetings. Can I get compensation for the extra work I did? I don't have written proof of the raise but I do have her email about the promotion. I work in Texas if that matters. Thanks.