sores on cats head HELP PLEASE

Hi there, sorry for long question, I have a 3 year old female cat named Agro who has 2 sores on her forehead that won't heal. it started about 3 weeks ago, while stroking her I felt something in her fur which closer inspection was a small scab, the next day she had 2 more scabs on the other side (between her eyelid and earhole on both sides), day after that I came home from work to find both sides red raw an her left eyelid had swollen, she had 2 bald patches an the fur around the sore was wet as if they'd been weeping. I took her to the vets next morning who said it was a reaction possibly to food, she always has the same food but I was worried that the week before I applied muscle rub on my shoulder an thought maybe I'd touched her. the vet wasn't very helpful an said no probably the food, he gave her some tablets for allergy?!? 7 days tablets an go back if it didn't work. it's been 7 days after the tablets stopped an the patches are bald, most of sores OK now but 1 side is sometimes red and weeping (I think coz she's washing it an scratching off the surface). can anyone please tell me if it sounds like allergies, I don't totally believe the vet as I haven't changed her food and she only goes in the garden (I can attach a picture) an why it isn't healing. also how can I figure out what she's allergic to?! thanks, Ashley X

I think a second opinion is in order.  Do you know another vet you can take her to?

PS. She isn't scratching at all, no other symptoms, eats an toilets as normal... But I did find a dead sparrow in my kitchen day before the scabs appeared. I do have another cat who is the hunter (Agro can't catch anything) but worth mentioning as I suspected she helped with the murder

Thanks for quick reply :-) yes I can go to another vets but wanted to try forum first, she was a feral kitten who I have made very Mard an cowardly so every trip to a vet is extremely traumatic for her (an me).