Buying meds without prescription for ferals

I need to buy pain med for feral kitten with shattered hip I took her to vet and he said use benedryl However she hates it and foams at mouth vomits etc I want something I can inject for her pain Can anyone help me please My baby's name is Santana and she is precious I can't stand to see her in pain. Please help me help her

I'm not sure why he'd say to give benadryl for pain.  Benedryl is an antihistamine.  I would ask the vet for either a pain shot (not Metacam) or for a liquid pain med.  Some come in a syringe that you squirt in their mouths.