I Am A 64 Year Old Woman And I Believe

I am a 64 year old woman and I believe I have been bitten by a spider( not sure what kind ). I am overweight so I did notice it until it starting hurting right under where my stomach skin hangs over some. Had my husband look, it is red, swelled, and purple with a black dot in the middle of the purple. My husband said it was draining today, so he mashed on it and yellowish red stuff came out of black hole. I have used peroxide, soap and water on it. Is there anything else I can do?
It is tender and it hurts to be pushed on or around the swollen area. Should I go to my doctor or wait to see if it will heal on its on.