Feline Herpesvirus

[Midgie]

My cat,Stormy,is 7 years old.Last fall he started getting sores in his mouth.Because of them he couldn't hardly eat and lost weight.The vet thought he had bit into an electrical cord and put him on antibiotics.He immediately got better.About 2 months later the sores came back.The vet put him on an antibiotics again.He showed immediate improvement.About 1 month later,the sores were back.I took him to a different vet who thinks he has herpersvirus.He out Stormy on an antibiotic and B-12.He started getting better,but a week later was crying again from the pain.He doesn't drool and from what I have read,doesn't have symptoms of herpesvirus.Any answers?Help?