Thanks for query.
There seems to have two possibilities of having lump in front of ear.
1,Due to removal of upper two teeth there is possibility of having some infection spreading to lymph
node in front of ear.
2,There is having a chance of Infected Sebaceous cyst
As you have done a course of antibiotic,wait for few days and see the improvement.
If there is no improvement then consult your doctor for the diagnosis.
Ok and bye.