Hello Doctors, I Am 60 Yrs Old And My Problem

Hello Doctors,
I am 60 yrs old and my problem is when I use public toilet, I get rashes on my penis. Also if do not take sugar tablets for few days the same thing happens. My sugar level is less than 200 reading after food. The fore skin does not go back and if I try pull it back I get skin cracks in the penis and it is painful. Can you suggest permanent remedy medicines. But why it is happening.
Thanks and regards,
Shekar