You really need to see a doctor. I'm not sure why you'd be embarrassed because to your doctor, your penis is just another body part.
Also, you are 64. Have you had any prostate testing done or had any check ups?
There could be a number of reasons this is happening - bacterial or fungal infection, another skin condition, etc., and the cure for it depends on the cause. Only a doctor can tell you what the cause is. Please don't be embarrassed to go see a doctor.