There is, really, very little that can be done to "fix" this issue.
You can get some minor increase in size and thickness with surgery by an experienced urologist.
All the stuff that Dr. Google tries to sell you to make your penis bigger? It is ALL a scam and none of it it will help you.
So. What to do?
See a urologist who has experience with helping patients with micro penis.
No diet, no exercise, no supplement, no machine, no gizmo is going to help....and many of these thing can do harm.
Does this make sense to you?
It's safe for you to press the positive feedback button now if you so desire. And, never fear, even after you press that button I'll still be right here to continue helping you, but, as I do work for tips, I want to make sure you are happy before rating me.
Dr. Rick MD FACS