Now, while an agent is certainly not your personal genie (remember Disney's Aladdin? "Poof! What do you need? Poof! What do you need? Poof! What do you need?!"), remember that once you have representation, your agent's job is to do everything in his/her power to sell your book and make it a success. So, as I've said before and I'll say again, if you review your book's cover art and are displeased:
• Breathe. The following steps will be of no use to you if you don't continue to do so.
• Tell your agent as soon as possible. (Preferably during business hours.) He or she will be able to discern whether your concern is 1.) appropriate and 2.) something that can be addressed/fixed by the publishing house, and will then do everything he/she can to communicate the problem to the editor/publisher and get it fixed.
• If, as in Brenda's case, your agent is temporarily unreachable, write an e-mail to your editor. Please calm yourself down before you do this. Don't send an e-mail or make a phone call in anger or panic. This is never a good idea.
• Look on the bright side. Best case scenario: the publisher eats the cost of a cover adjustment and all is well. Worst case scenario: nothing changes and your sales may suffer as a result, but it's very unlikely your career will be tanked. Most likely, some in-between scenario will occur, and you're likely to emerge from it relatively unscathed. And if your book is coming out in hardcover, remember—there's always the paperback.