I don't see it. Yes, CVS stores are typically open 24 hours a day - but their pharmacies typically are not. If the theory is that SG and JB obtained a scrip before/during this "lost time," they would've had to have found a CVS with a 24-hour pharmacy. The closest CVS to JB's place in Oak Beach appears to be the location at 150 South Wellwood Avenue in Lindenhurst, NY. That location's pharmacy closes at 10:00 p.m. on Fridays. As the aforementioned "lost time" is believed to have occurred after 2:00 a.m. on Saturday, May 1st, that discounts the possibility that the two could've gone there.
The only nearby CVS with a 24-hour pharmacy is located at the intersection of Montauk Highway and County Line Road in Amityville. I may be way off, but I'm assuming there's no way SG and JB can make it from Oak Beach to Amityville and back again in that fifteen to twenty minute window. Yes, the city of Amityville is geographically close to JB's place in Oak Beach, but they're quite far apart by car. He would've either had to have hopped on the Robert Moses Causeway north to Montauk Highway (the quicker of the two routes), or he would've had to have traveled west on Ocean Parkway, north on the Wantagh State Parkway and finally east on Montauk Highway.
To be clear - I definitely think they obtained drugs during that "lost time." I just don't think they obtained drugs that required a prescription.
Note: Apologies if some of this has been covered before. This is only my second post, but I feel like I've gleaned as much from this thread as I possibly can.