About 4 Months Ago I Rolled My Foot Over On

about 4 months ago i rolled my foot over on some lava and abraided the skin. since then on the outer edge of my foot underneath is red and white pimple like spots..painful to touch..i went to a hollistic healer who did an ozone treatment and it worked for awhile but never went away..when i went back to the mainland i went to see my primary care who gave me a z-pack antibiotic and told me to keep it covered.. seven days since taking antibiotics it is flaring up worse then ever. sore to touch and a little swollen.. is it normal when on antibiotics for the issue to get worse before better? they said it was staph......