Men's Health

The outer foreskin layer contains sensitivity nerve endings which respond to gentle touching during the early stages of sexual arousal. The sensitivity nerves of the inner and outer foreskin contribute to the experience of penile stimulation, up to and including orgasm. A "short foreskin" may be an indication of a deformity problem that is affecting the nerves endings.
I think your theory is right, since the short foreskin exposes the penis head, the skin has dried out (which is normally covered by the foreskin), and this could possibly have affected the nerve endings in the skin. Try some mild over the counter lubricant from the pharmacy on the head of your penis and see if that helps. Getting and keeping moisture to the penis head skin is important.