I have Strep throat with the telltale white patches and fever. Doctor prescribed me amoxicillin-clav 875 - 125mg tablets once every 12 hours. It's been 18 hours, I've had 2 tablets, but the spots are actually getting bigger and more numerous. Do I wait before I call my doctor and ask if maybe we should try a different antibiotic, or should I wait? Should the white patches be starting to recede at all yet?