DON'T PUT OINTMENT ON IT.......It's a spider bite. Mix baking soda and water into a thick paste nd put it on the spot....Let it dry to a crust then peel it off and reapply over nd over for the next several days. I 've been bit before and if you apply ointment over it the skin can heal too fast locking in the venom which can lead to ...yep, Mersa....I worked in commercial pest control years back and was bit on my lower leg. It swelled to one and a half times the size of my other leg before I realized what I did wrong. Most people never know when they're bitten because you don't feel it, it doesn't sting or burn at first and 99 out of 100 Doctors don't know how the diagnose it properly.