Lol literally Google pharmacies right after a border crossing. There will always be some guy hanging around. Just say "You're worried about customs" and he'll take you to the back.

They don't hide it all all. Dude gave me a business card.

Also: Sometimes depending on the pharmacy and controlled substance, they'll require a prescription. So they'll recommend a dentist who will write one for $50. For anything.

Or if you feel lost, in the area around the border, you'll see the occasional guy asking you if you need any medication. They will then guide you to the pharmacy, perscription, etc.

My debit card was being declined one time for unknown reasons, dude straight up gave me a bike so I can "cut in front of cars" at the border, go to an American ATM, come back.

I used to always bring a few hundred Xanax and Adderall for personal use. Declared to Border patrol agent, no problem. Worst I got was "Next time have a us perscription" (for adderall) or "This is strong stuff" for the Xanax. But one day the border agent said "nope". So like a moron I had my pills dumped into a 80 qty of Penacillin tablets. Border dude immediately knew (probably saw crossing notes), and from the weight said he would count them.

Went to back room of facility and supervisor asked if I knew what I just did. Said "Biggest fuck up of my life" and said to see a psychiatrist would take months and my current mental state needed something now. Mentioned when I returned the bottles to the pharmacy they gave me Amoxicillin and said it was similar. Let me go no problem for some unknown reason but now my passport is flagged.

So moral of the story, 9/10 customs agent don't give a fuck. If you do the "hide meds in dog medication bottle" trick, don't have a history of crossing with perscription stuff.