question: I have had an infection below my left back molar for a long time.  Had a root canal in July and pain is back once again.  Dentist put me on Amoxicillin and sent me back to Endodontist.  Amoxicillin wasn't working so endo changed it to Clyndomyicin four times a day.  That was Tuesday and now it's Sunday.  No relief. Infection feels like it's getting worse.   Yesterday I woke up with a circular sore on my inner thigh.  It's red, itchy, bumpy and is white on the inside of the circle.  What could this be?