Hi,
Metformin is for insulin dysfunction (I know because I have it). If you have sexual issues related to blood sugar or insulin, it will work. It won't work for other uses.

Abilify is less likely to cause sexual dysfunction, but doesn't repair it. Sometimes people switch to abilify from other atypical antipsychotics, because it's less likely to cause issues.

Wellbutrin can sometimes repair sexual issues caused by SSRIs, not sure about other medicines.

If you really do have clinically high prolactin, it is treated with bromocriptine or cabergoline. I know because I have a prolactinoma, which is a small benign hormone-releasing tumor that can occur in men or women. Sounds scary, but completely treatable with a tiny little pill taken 2x week. To diagnose it, it's just a blood test, sometimes followed by an MRI if prolactin is actually high.

Low testosterone can cause issues in men, too. I believe that's a treatable thing also.

You'll need more information from your doctor to confirm the reason for the issues you're having - I'm just listing some things you might want to ask about.