Your cat may also stop meowing completely.
Your vet needs to do an exam to determine the cause of the sore throat and figure out an appropriate treatment based on that diagnosis. Your cat’s vet may also perform an endoscopic exam and/or culture of the fluid in the back of the throat.
You can also try chopped up sardines or roast chicken. You may also ask your vet about an invalid diet.
If the cat has an infection that affects the throat, the vet will prescribe antibiotics. If the sore throat is caused by inflammation from an allergic reaction, the vet will prescribe steroids.