I am 24 and 3 years ago, my body started itching all over and I had a prickling sensation all over my body like bugs were crawling on me, but no rash whatsoever. For the past three years, I have been on an endless search from doctor to doctor, blood tests, skin biopsies to no avail. Everything comes up negative and doctors look at me like I am crazy, because I look completely normal. There is no rash, bumps, hives, to see how bad I am suffering.
I, too, suffered steadily-worsening itching without rash for years. I just wrote it off to generic eczema until I finally stumbled across celiac/gluten intolerance as a possible culprit for many of the symptoms I had been suffering. Since going gluten-free earlier this year, the uncontrollable itching has mostly resolved itself - but it took awhile. I didn't really suffer any visible signs of rash other than when I scratched so much that I irritated my skin, although the last few months before I went gluten-free I did develop dermagraphia where I could basically write on my own skin by lightly pressing on it. You can imagine how red and bumpy my skin looked whenever I had an itching fit!
At any rate, just offering my own experience to encourage you to stick with it for now. You can't really judge if it's truly helping you for a couple of weeks at least, from everything I've read. For some people it takes even longer.