Nope, your curls probably won't return if they haven't by now. That's why I've tried to get the message out that the BKT curl relaxation is often permanent, in spite of what the manufacturers, retailers, sales reps, or salons/stylists tell you. The finer your hair texture, the less likely the curl is to return.
I avoid any and all oil in my products--oil absolutely kills my curls. I don't know how anyone uses products with oil.
The permanent nature of the curl relaxation works well for me. I've been BKTing for years, and I love it. Because it's permanent, I only have to do my roots now. One application is all my hair takes, but I wear my hair curly, not straight.