I use them whenever I can. I don't see what could br wrog with it as long as you are staying hydrated and don't spend too much time in there. I always thought of it as a cleansing thing moreso than weight loss.
Today is a new day. You will get out of it just what you put into it. If you have made mistakes, there is always another chance for you. And supposing you have tried and failed again and again, you may have a fresh start any moment you choose, for this thing we call 'Failure' is not the falling down, but the staying down.