First, don’t panic. Panic raises your heart rate, which spreads venom faster (and also makes you look silly in front of your cat). Wash the area with soap and water. That’s step one and step two.
37 Types of Spider Bites: Identification with Pictures (Symptoms )
Apply a cold pack to keep the swelling down. It feels nice, and it makes the spider look like a wimp. Pop an antihistamine if you’re itchy, or take ibuprofen for the swelling. Basically, treat it like a cranky mosquito bite that owes you money.
Draw a circle around the redness with a pen. If it gets bigger than your thumb, or if you feel seriously unwell (short of breath, chest pain, swollen tongue), head to urgent care. But for 99% of us, it’s just a few days of ugly skin and a good story.