I am 23 years old.no hair on face.Testosterone in my blood is 679ng/dl. what is the medicine please........?

Your testosterone is normal. So that isn't the problem. It may just be genetics. My beard was not very full until I was in my 30s for example. You don't want to take T supplementation when your level isn't low because it can cause a lot of problems. Of course shaving does indeed help a bit. Also, you might consider using rogaine.