question: Wednesday I had a root canal done for a tooth that was feeling sensitive but I had no pain or swelling but the root was abscessed and did have infection around it.  Anyway, the root canal went fine and the doctor gave me some antibiotics...Kflex. I started right on them when I got home along with Tylenol 3 for pain.  The next day I was feeling somewhat better but still had the normal soreness, pain etc. from the root canal.  I was taking a shower around 10 am and noticed a red hard bump near my armpit/breast about the size of a quarter.  This is the only one I have on my body and it is bothersome and painful, but I am leaving it alone.  It has gotten a little bigger since Wednesday with a little more redness.  I am thinking it is a boil or a bite of some sort or because the infection I had in my tooth was no longer limited to that area any more and it is showing up somewhere else and it will just take time for the antibiotics to kick in!!  What do you think?  Also, I have been running a low grade fever (99.2 the highest) since Thursday!