Should he go to the ER...is this staph or a spider bite?

My husband has had this for 4 days now. the location is on his upper thigh towards inside of the leg it started like a little pimple and he popped it, the next day it started to get red around it like a ring and it has been getting bigger and bigger, he squeezedit and a very small amount of white goop came out and its hurting him to where he can barely walk, it is now about a 6-8 inch wide circle, should i take him to the ER or is there something i can do for him here at home?