I have used a body massager since I was 12 – as a matter of fact, that's how I discovered masturbation. It broke I while back, and I haven't used one since. Will I regain any sensitivity having not used it for a while? Or is the sensitivity loss permanent? This is the first I have heard of this – although I have noticed the sensations aren't as intense as when I first started several years ago.
I don't have any specific information on this, so don't take my advice as absolute truth. A certain degree of desensitization is entirely temporary, the sensitivity coming back within minutes. But I believe that if you use an intense, artificial stimulation source regularly over an extended time period, you will experience a certain degree of permanent sensation loss. Part (perhaps most or even all) of this may be psychological, since your hand simply can't match the amount of stimulation provided by a machine. I wish there were more empirical data on this phenomenon; if anyone knows of any, please let us know.