Hi.. Can understand your concern.. As per your complain swelling and pain after the filling of tooth happens when the first filling has fallen and the tooth is cleaned to retain the second filling there are chances that the nerves and blood vessels present in the centre of the tooth in a small chamber known as Pulp chamber gets exposed leading to irritation of the nerves by the filling material which is accidentally placed on the nerves.. This causes inflammation of the nerve and the inflammation leads to severe pain and swelling and in this case only cold or hot compresses cannot help.. You should immediately visit a dentist and get an x ray done and if the pulp exposure is ruled out the filling has to be removed under local anaesthesia and the antibiotics and anti inflammatory painkillers like Advil should be given to the patient and the tooth should be treated with root canal treatment in which the nerves and blood vessels are removed , the root canals are cleaned and when the pain completely subsides the filling is done.. Cold compresses can be done along with it to get relief and should not do hot compresses as it can further increase the inflammation.. Hope this information helps.. If you find the answer helpful kindly write a positive review and click on found this answer helpful as a token of appreciation.. Thanks and regards.. Dr.Honey Nandwani Arora.