I Fell And Hit My Hand On Something (unknown) And

I fell and hit my hand on something (unknown) and received a small, roundish poke that perforated the skin. Now (a few days later), the scar is still a little red and swollen, but the surrounding skin area is bluish/greenish. Should I be worried? If the object that I hit it on was metal, what would be the signs of rust entering the wound, if any? Thank you.