Hi my son has been to the doctor twice in the last six months, both times treated for strep throat. the first time it took two week to clear the infection. he went to the doctor three days ago , again the penicillin, is not helping. he went back today they have scheduled him for a cat scan. he may have an abscess, they are saying may need to be surgically remove. can you please explain, why there would be an abscess, caused from strep throat,