Hii , my cat has a infection on the side of her lips would it help i put salt and water?

.. the vet gave her Prednisolone 5 mg and said she wasn't sure if it would work .. so its been a while that she taken those and the only thing that it did was get a little smaler but just a little bit .. so yeah i was wondering should i put salt and water on it and would it help to the the infection out of there ?! . thx :p