Suggest Treatment For Stinging Pain In Between Fingers After Spider Bite

I think I got bit by a spider about a week ago. It bit me during the night in the web between my ring finger and middle finger. I woke from my ring finger on my left hand stinging and hurting. Since then, it has been itching, terribly, and now, the top of my hand, above my ring finger has a large welt. Do I need to see a doctor?