 [ Symptoms ] is it risky for a diabetic to get a tattoo [ Disease ] there are plenty of other effective antibiotics like erythromycin or the cephalosporins some penicillin allergic people may have a cross over allergy to this class however he needs to be under the care of a good dentist now let the dentist determine the type of treatment and antibiotics if he has an abscess he needs more than just a prescription for a non penicillin based antibiotic dental infections like you are describing need immediate and definitive care