Verified answer

Probably not a bite at all, and of all the biting critters, spiders are the least likely.

http://news.yahoo.com/surprising-cause-most-spider...

Here are some photos of what spider bites look like:

http://www.medicinenet.com/image-collection/black_...

http://firstaid.about.com/od/bitesstings/ig/Spider...

Mosquitoes aren't just annoying. Scratching a bite can cause a skin infection. Also, mosquitoes can carry serious viruses and other diseases. To protect yourself from mosquitoes, apply insect repellent and cover up when you go outdoors.

It's hard to tell if a spider or mosquito bit you, if you got an infection, or if it's something else. Unless you saw the insect do it you won't know for sure, and they ask you to bring a spider along for identification purposes, but I'd rather take a photo of it scuttling away than kill and put it in a baggie.

I have severe arachnophobia.

Call your doctor or go to a clinic if the symptoms worsen. I'd call the doctor anyway if symptoms are annoying or have been there over a week. It's too hard to tell what it is from online.

Could be having a allergic reaction from the bite....or it could be a spider bite...get it checked out

It might be your nipple.