Any vets?

My dog is a pit/American bull dog mix and has had troubles with allergies lately. He was on meds from the vet and antibiotic and anti fungal pill to help. That all cleared up but now I’m noticing inbetween his toes on one foot is starting to swell again. Any advice on what I can try at home? It was SO expensive for the meds, of course if that’s what it comes down to I’ll take him but just trying to find natural remedies before spending 400.00 in medicine that last a month. I was reading it could be a cyst from irritated hair follicles due to allergies.

It’s not an open site or bleeding just swollen and a lump