You'd need to get a prescription from a doctor, and then go to a compounding pharmacy. You should call ahead though and see if they actually have the means to make it. The PCCA announced in 2009 that US compounders were out of stock, and that manufacturers had stopped producing it. They may still have it overseas.
If you are pursuing bottom surgery and your surgeon is requesting/requiring that you use it, they should be able to tell you where to get it from.