Have a blister and i think it came from a spider bite, it's been 3 days and the blister went from looking like it's about to bust on day 2 and now deflated on day 3. it's as round as a nickel. will it just go away with no treatment or what is recommended

See below: As long as there is no pain, swelling or sign of infection. It should heal fine.

See below: It could be from a spider or a lot of other insects too. The things to watch for are increasing redness, swelling, warmth, pain and/or red streaking moving toward the center of your body or oozing pus-like material. If these occur, seek medical attention asap.