What are your concerns? Sadly, sometimes the best option we have is to remove and figure out what it is. Express your concerns to your veterinarian, ask lots of questions of your veterinarian, let her know what you will agree to, and make a decision from there. For example, my vet knows that if the mass is too deep, invasive and is going to create disfigurement or have a long painful recovery that I would rather not go through with that and deal with whatever it turns out to be with a palliative care approach.
I'd also question to see if she would agree to an oral antibiotic run. In my experience creams just don't do the trick sometimes you need a bit more of a systemic approach to get rid of the issue.
Another question to ask is if a fine needle aspirate of the spot could help with diagnosis. My vet often will do an FNA to get an idea of what is inside the lump. Depending on what he sees under the microscope often tells us if we want to try an antibiotic round or just go straight to removal. FNAs are not as good as excision to biopsy, but sometimes they can help.