How can I tell if I need antibiotics for a finger infection?

Swelling. If the areas swollen or has a di i would recommend antibiotics. A closed swelling on the finger xan embarrass the blood supply. If the infection is is not getting better in 1-2 days it may be better to see doctor .
Abcess, streaks. The redness of the infection should be improving daily. If you are experiencing increasing pain and swelling, develop red streaks traveling up your hand and arm, have a fever, or have a large swollen area that feels boggy, you should consult a md asap.