I wouldn't recommend you to use the medicines...
Moreover, you are about the average..
A non-erect penis usually measures between 8.5cm and 10.5cm (3-4 inches) from tip to base.
The average figure is about 9.5cm (3.75 inches), but this kind of precise measurement is rather valueless. Many factors can cause a temporary shrinkage of two inches or more, for instance cold weather or going swimming, so you needn't worry if you happen to fall short of the average figure.
Of course, it's true that some men have big penises and some have smaller ones, just as some men have small feet and some have big feet, but the measurement is not - repeat not - an index of virility.
No matter how often it's written that penile size doesn't matter, and that women aren't attracted to a man because of the length of his organ, the average male continues to think the same way.