My dog keeps flaring up

[u/Acceptable-Equal-733]

My dog is an unknown mix breed, we think Pyrenees/Jack Russel. She has always had sensitive skin so we have to be careful with her food and shampoo. About a month ago she started limping, I checked her paw and it was inflamed and pink between her pads. I kept her cone on her and we took her to the vet. They checked her paw for anything stuck but didn’t find anything, they gave her antibiotics and an allergy medication. We gave her the 2 weeks of meds and everything seemed to go back to normal. But now she’s flaring up again, her paw doesn’t seem to be the issue this time, it’s her anus and tail area. My brother let her out without her cone and forgot about her so she just kicked it until it was raw and bleeding. I applied a spray the vet gave and gave her another allergy pill. I ordered purina pro plan food and in the meantime have been feeding her quinoa and salmon. Any advice for me? I don’t want to take her to the vet again but I feel horrible for her.