Hello Welcome to HCM Reviewed your husband s history. He has been on anti coagulation with warfarin and is on regular follow up a Physician with INR. Regarding his symptoms of small swelling itchy swellings over his scalp with pus, this could be due to skin infection. Warfarin is an oral anticoagulant which is a blood thinner, it delays blood clotting mechanism hence has major side effect of bleeding. Bleeding can be superficial following minor injuries or can be internal from gut etc. But pus oozing itchy lesions with warfarin is an unlikely side effect. Regarding to the medication prescribed by your dentist, it is difficult say without information on drug prescribed. But usually dentist prescribe antibiotics prior to procedures. So it is advisable consult a skin specialist (Dermatologist) to come to a correct diagnosis and get appropriate treatment. Carry your all medications during consultation which cold help the doctor to rule out any side effects from them. I hope u find this info helpful Wishing u r husband speedy recovery and good health.