Hi, You have ot mentioned about the type of treatment undertaken which corrected your problem.If it was a surgical extraction in the 2nd or third molar area, it may have caused some compression/damage to the inferior alveolar nerve because of which you are feeling this numbness in your underlips region. The nerve usually heals on its own. You can take supplements to enhance the regeneration though which can be prescribed by a Dentist.

Dear Kamal, we generally prescribe cyanocobalamin to be taken daily in such cases.One tablet has to be taken daily.There are many brands available like neurobione forte.
Take one daily for a long time.

Hi Kamal,
The symptoms what you have given i.e., pus formation and inability to open the mouth are definitely not due to the medications what you have taken. It might be due to pericoronal infection i.e., infection and pus formation inside the flap tissue covering your last molar tooth due to its incomplete eruption. This usually causes these symptoms. The lack of sensation in your lips might be due to the compression of your Inferior alveolar nerve by roots of erupting last molar, which usually gets relieved by itself. So better contact an dentist and get an x ray done for the last tooth to confirm the diagnosis.