I SCRATCHED MY KNUCLE WHILE SCRAPING A FENCE THAT I

i SCRATCHED MY KNUCLE WHILE SCRAPING A FENCE THAT i WAS PAINTING. iT SEEMED TO HEAL, WITH A LITTLE SCAB ON TOP BUT ABOUT A WEEK LATER A RED, SWOLLEN RING APPEARED AT THE WOUND. IT BEGAN TO GET SORE WHEN TOUCHED, SO i THOUGHT MAYBE A SPLINTER, BUT NOT ONE THAT IS VISIBLE. wHAT SHOULD i DO? tHANK YOU