What Must I Do After Stepping On A Rusty Nail And Having Worsening Foot Pain Days Later Without Knowing My Tetanus Status?

I stepped on a rusty nail 4+ days ago with full body weight. The nail penetrated through my tennis shoe and sock into the front padded area of my foot below the 3rd and 4th toe. I can't remember the last tetanus booster i got. The pain was excruciating and still has not completely gone away... in fact today i noticed the pain spreading to the top of my foot in the joint areas of my 3rd and 4th toes. I still cannot walk on it normally with full weight without considerable pain. No unusual discoloration on top or bottom. What should I do?