Cut thumb across MCP

I cut my thumb across the MCP joint on a sharp object taking out the trash. My thumb was flexed when it was cut. If you divided my thumb laterally down the middle, the cut covers the half closer to my body side, rather than my pinky side. The pain from the cut made me feel like throwing up. I think maybe I was close to fainting because my husband's voice sounded all muffled. The doctor looked at it a couple days later. He moved my thumb towards my pinky, rotated it in a circle, pushed on my thumb and made me resist his pressure. All of that was fine. I tried telling him that it still really hurts to pick up paper. I have been wearing my thumb in a special little cuff thing I bought at the drugstore. I have been noticing it hurts when I reach and I try to grasp something with my thumb. Putting my arms through sleeves is a big problem. The pain occurs from the cut up towards the first joint in my thumb. My doctor didn't seem to think anything was wrong other than maybe some cut superficial nerves because above the cut is numb (not total loss of feeling, but numb). It hurts so bad when I do those movements, that I wonder if he overlooked something I cut. I wasn't able to communicate to my doctor which movements made it hurt because I didn't really know at the time. Any ideas what I could have cut? The pain is so bad when I make these movements. Its not a pain I can suck up. I immediately have to stop the movement.