After Getting An Impacted Wisdom Tooth Extracted, I Quickly Developed

After getting an impacted wisdom tooth extracted, I quickly developed blisters/lesions/ulcers on my gums and cheek which are whitish in color and hurt. This is going on the 3rd week. I was about to start on the Amoxicillin script I'd been sitting on, but now read it can actually cause thrush and definately will only kill bacteria and not fungal issues. My tounge is not super white, but a little, and there are some red spots on it. Is this thrush, or what do you think?..