BTDT. twice. First of all, I am diabetic and have to watch for cuts, wounds...  Ten years ago, I wasn't feeling well and when I started to vomit, I went to emerg. Dr. found a small open crack on my heel. Blood tests showed something so they started me on an IV; did that for 8 days, then 2 weeks of oral antibiotics.

This spring I wasn't feeling well and had a sore knee cap, warm to the touch; went to emerg, couldn't find any open cuts, but blood work showed elevated white cell count; test also showed clotting ability reduced; 7 days of IV, then 2 weeks of oral; mystified as to where infection started until I remembered I had had a molar extraction 3 weeks earlier.  Could they be related? The body and its workings defy logic and medical understanding/knowledge.
At one time, SOP was to start a course of antibiotics before extractions on high risk patients. Now, they worry about antibiotic resistance and treat problems as they develop.
Luckily, this was all covered by universal health care.