Bug bite thats caused baseball sized reddish looking rash with purple bruising?

Hello we're in central Illinois and went camping over the weekend my friend first noticed the bite on Saturday which looked like a mosquito bite. It was normal skin color and about the size of a peanut M & M. It was itchy. On Sunday the bump was gone and in its place was a large reddish rash with bruising. It is not painful to the touch but itches sometimes and does not appear to have gotten bigger than on sunday although the bruising has gotten slightly more purplish in color there is no signs of puss or any type of fever. The reddish color literally looks likes someone punched you in the stomach several times but with 4 day old looking purple bruising. We were attacked by mosquito's and chiggers that weekend and its deer tick territory out there...we also have brown recluses in that area i've never seen a bite like that. What do you think it was? Shes trying to avoid a hospital ill if she can....what do you think?