Need advice to diagnose my general head discomfort.?

its very possible for the infection to spread. you should have been on antibiotics before the tooth was even pulled. the diarrhea could possibly be your body's reaction to it,i dont know if the ears ringing is good or bad because that can be caused by pressure change. the aches that you're getting are signs of a spreading infection. start with the ct scan and go from there. with doctors and dentists i find it best to take what they say and then go with your gut. its your body,your health. good luck with everything.