That sounds pretty reasonable for The One actually. It's not so much a mass builder as it is an aggression/ recovery enhancer. Iirc, it is originally a compound that was designed to be given to (i think German) Olympic athletes before matches to make them more aggressive. You should notice that it leans you out and makes you rage in the gym, but don't expect a ton of mass.
That said, it shouldn't be giving you itchy nipples. It's pro-m-dht iirc, and so it should have a pretty androgenic profile, meaning if anything it should help fight gyno (I actually read recently about a guy using its clone, d-plex, in a combination of drugs to eliminate his gyno). Definitely keep an eye on the problem, and if it gets worse you should stop use and go into PCT.