My 13 year old cat has one red ear with dried blood in it. He started shaking his head quite a bit a few days ago. I figured it was ear mites, so I originally cleaned them both and put some drops in his ears. It got worse the next day, and when I tried to touch it, he hissed at me. He seems to be better now, but I'm worried that I may have let it go on too long. By the way, I have a very low income, and can't afford to pay for a regular vet.
You need a rx from a vet for any antibiotic for the ear. You can try ear cleaners such as nolvasan otic or oti-clens. Ear mite meds are also sold over the counter. It sounds like your pet needs a vet visit. vetcare