Neither of my boys got pain meds. I asked about them and they said that for the boys as long as the neuter is normal (and there isnt more trama than usual) then they give pain meds at the time of neuter and once while they are in recovery but do not usually send them home as they are not needed. So this might be how your vet feels as well. She said that since rabbits have sensitive tummies sometimes the extra pain meds just make the bunnies groggy and less likely to eat which causes more problems in the long run.
Did you bring both boys to the vet together?? I *thought* (might be mistaken) that Penny and Max were bonded already. If they are bonded then no you shouldnt keep them seperate. You might want to rub a towel all over Max to get his scent and then rub it on Penny (so he smells like Max and not like the weird vet place) before you introduce them again. If they were seperate today even though they are bonded make sure to keep a careful eye on them tonight that they are acting normal.
If they are not bonded yet then you should wait at least 1 week for Penny to heal up before starting the bonding process.
I hope Penny feels better!!!! Keep an eye on his eating and pooping tonight!