Thanks for your question, I am Dr Asanghanwa Carlson, it is not a normal happening to have purse oozing from a scar three months after a surgery. But pus is generally a collection of bacteria and dead blood cells which had collected at the site of the scar. I would advise you consult the physician/surgeon who carried out the surgery so that he examines you properly and if necessary open up the scar and drain the pus and do proper test on it so as to prescribe appropriate antibiotic for you. Good luck