What Bug Could've Bit Me?

Was up trout fishing in Michigan, walking thru woods by a creek. When I got home later I noticed my foot felt numb and there were 2 sets of tiny "bite" marks on top of my foot in somewhat of a bulls eye pattern around it. The top of my foot was going numb and started going about 1/2 up my leg. Went to walk in care-was given an antiobiotic which I took for 2 weeks. We had found a wood tick amazingly on the outside of my clothes, but the dr.'s said although it might've been that--the numbness wasn't adding up. 3 weeks later the top of my foot still feels like I had a shot of novocaine there. No festering of bite marks, no itching, no swelling, just numbness. Doc's are scratching their heads. Any ideas?