How do I import medicine?

Hello!

I'm a Dane who has been staying in Tokyo for almost 2 months now, and while I was supposed to go home next month I've been given an opportunity to stay a little bit longer.

However there is a slight issue. I don't have enough medicine to cover this extra month.
I brought some prescription medication from my home country when I went here (Alongside all the import documents needed for more than 1 month's worth of medicine)

I am able to get someone to pick it up for me at home, however it's the getting to Japan part that's the problem.
So I was wondering, Can I just get my friend to fly over here with it? Or would that be breaking the law as it isn't his medicine.

And if he can't, how can I send it here using mail?

Hope you guys can help me.