Suggest Treatment For Allergic Skin Reaction To Spider Bite

Hey i got bit by a white tail spider and now my skin around the bite looks like a really dark bruise like a banana and its a bit bigger than a 50c coin (AUD). I read online the only thing i should be worried about is if the skin starts blistering but should i see a doctor anyway or will they just tell me to come back if it starts blistering. I m a bit worried about necrotic arachnidism but it could just be self diagnosing thats freaking me out. Best regards, Leland