Help Desperately needed

Help Desperately needed

I need some urgent vet advice. I live in Muscat in the Middle East. For the last 2 weeks there has been NO vets in town - all on holiday!!! I think my cat was bitten either by a snake or another cat and it formed an abscess. She burst that herself. I found some antibiotic powder in a chemist over here, but she has still got low grade fever and is not putting her foot to the floor at all. Does anyone know if it is safe for me to give her human antibiotics and what kind of dose I need to give? Big ask I know, but as i said, I am desperate!! Thanks in advance from me and Tabitha