Verified answer

My love has played guitar heavily for 15 years. He has the same exact problem. He can't use my phone because the touch screen doesn't register with the callouses. Almost like it doesn't sense skin. It's common whether the callouses came from guitar playing or any kind of work. His father has the same problem and I have a few musician friends with that issue as well. Callouses can decrease sensitivity because I've been learning to play the acoustic guitar and have noticed a change in sensitivity on my fingertips.

: )

The best way in my opinion is to play and play as muchas you can. I found that when my fingers hurt the most, like when I could see the marks from the strings that dug in my fingertips, I stopped for only a few secs then kept playing so my fingers couldn't heal. The less healing, the faster your calluses will grow.