If you self-publish, and have sold lots of books, you're to be congratulated. It's quite an accomplishment. However, do you really want to advertise the fact that you are self-published right on the back cover of your book??? We've seen a few books that do just that - as though the fact that the book is self-published is a selling point. It's not.
People who read "self-published book" on the back cover are quite likely to put the book down. Wait until you've made it big, you're on Oprah or are negotiating the movie rights. Then, sure, go ahead and brag about how you got your start as a self-published author. Please just don't do it on your first book. It won't help you sell books.