Thank you for waiting.
I understand your concern.
I am very sorry for your symptoms.
It is quite uncommon to have decrease in size of testicles in your age.
Some infection like orchitis can cause a decrease in size.
But you are not having any such illness.
It is likely that loosening of skin is causing an apparent reduction in size.
I feel you need not worry.
For confirmation,I would advise to take an examination by doctor.
I hope this information will be helpful.
If you have any query, please feel free to ask.
Your satisfaction is my goal.