You should first call your pharmacist and ask if it can be applied to the groin. Im not sure about the sugar or carbs making you sick, I think this is attributed to something else. You probably need to first find a new doctor, second have some blood work done, and third discuss your concerns with the doctor. Have them refer you to a urologist due to the sexual dysfunction. The urologist will have a better idea of what is going on because this is what they deal with every day and what they have studied for many of years. Find a doctor that will listen to you and never accept "psychological issues or depression" as a diagnosis when you know there is something wrong. Hope this helps.
Have you had any blood tests done for cortisol, and diabetes, also testosterone.
Maybe this is were i would start, then work from the results.
I do know that cortisol can make changes to sugar levels, it can also cause the skin to thin also.
I would have a cortisol , glucose, and testosterone blood test done .
I have never heard about creams which are steroids which you apply directly to the testicles,
I do know that to much cortisol, in the body, can cause lots of problems, and sexual dysfunction can be one off them.
Good luck
Nicola