Along Came a Spider?

Ellie woke up this morning with what we thought were more mosquito bites on her hand and wrist. As the day went on, we noticed more swelling and gave her some Benadryl. Then we noticed that a blister had formed. By 5 p.m. it was looking like this (the band-aid covers up a similar bite on her wrist)

At this point we thought it might be a spider bite. Brown recluse spider bites can leave a blister like this that eventually turns into an ulcer. So we decided to take her to the emergency room (really the only way she could see any kind of medical professional on a Saturday evening). After a rectal thermometer (ouch!) confirmed she had a fever, the doctor said that however she got bit, it was infected (probably a staph infection), and prescribed a couple different antibiotics. If the infection spreads overnight, we will have to take her into the Children's Hospital to get some I.V. antibiotics. We're hoping it doesn't come to that. Unfortunately, Ellie has historically had bad luck with insects.