My doctors orders have been to shoot sub-q testosterone and this has left a big lump then has swelled up under my skin and painful when i touch it. I have gone to the doctors and he said it was an infectiong and i got the medicine Cephalex. What are some of your experiences with getting infections and using anti-biotics to reduce the swelling and cure it. how long does it take usually to go away and who has used the medicine Cephalex.