Suggest Treatment For White Lump On Posterior Wall Of Throat

I have a white lump on the posterior wall of my throat; in the tissue; hard. I have been on antibiotics for nearly one week with no change. Not really any other symptoms, except a minor cough. I am planning on calling my Dr tomorrow but am worrying a lot tonight and would appreciate any info. I am female, 35, former smoker but over 10 yrs ago; I am generally very healthy. Thanks!