Elsa,
I'm also into alternative medicine and I have tried herbs like licorice, saw palmetto, green tea and most recently spearmint tea. These herbs have some effects when it comes to reducing acne and unwanted hair growth. Licorice has cortisol-like effects so it may work similarly in the body to dexamethasone. Spearmint tea has been shown in clinical studies to reduce libido in men and affect certain hormonal values (estrogen, LSH, FSH) in women. So this might be a good one to try. For me they have not worked 100% percent which is why I also use conventional drug therapy. Also, you'd have to go back and have your bloods drawn pretty frequently to check for your hormonal levels, I suppose, just to see if they are working. Herbs are not as potent as drugs and in high amounts some can cause undesired side effects, for example, licorice. You should use this with caution as it can cause a rise in blood pressure, water retention, potassium loss, etc. End result it could be deadly. So, always be careful when using licorice.
Also, try searching the Internet for alternative treatments and maybe you'll want to find an alternative MD in your area. Most don't accept insurance plans, though, and they can be expensive.
As for the dexamethasone and weight gain it's possible -- not everyone responds the same. My doctor also said that it was unlikely on such a low dose. But, after years of taking it who really knows -- I don't even think the doctors do. On high doses steroids are known to cause other problems like cataracts, glaucoma and bone loss. So, decades on a low dose might pose the same problems as well. It is definitely something to think about.
Hope that helped a bit.