Hello and welcome to Just Answer. I am a licensed veterinarian and would be happy to answer your questions.
I am sorry to hear that your cat is having this issue. Unfortunately, none of the experts on this site would be able to issue a prescription for medications. This type of forum is for information only and is not meant to dispense medications. On top of that, veterinarians are not allowed to prescribe meds for an animal that they have not physically examined.
Your best course of action would be to contact the vet who prescribed the meds a few years ago and see if they would be able to help you out at all. In the meantime, warm water and epsom salt soaks may help to relieve some of the swelling and discomfort if he will let you. If it is available to you, flushing the wound or site with an antiseptic solution like betadyne may help as well.
Good luck with him. Please let me know if you have any further questions.