What isn't working? Explain a little bit about the problem. Also, what OS, what version of Lightroom, a few details to help us understand your situation really helps. If the problem is that you can't see the tool when it's activated, try pressing the H key which is the toggle switch to hide/show the tool. Another thing to look at is the the flow adjustment on the tool. Without more information, I could guess and guess and guess. But I would just be wasting my time and yours.
Thank you but I got it working.