Please note I had to darken this to try and show the color difference better but it still isn't accurate - it is more like having a tan line 3 shades lighter than the surrounding color.  I have a bite that started out very tiny with no coloration last night, got a bit larger with color an hour later and was very large this morning (dollar size or larger) with very pink/red color and now is dime size in color with large ligher colored ring around it now about the size of a dollar size or larger. I don't know what bit me but it was itchy last night but itches only when you touch it today. I have a photo of it and it looks weird as if I got a tan on the outside of the lighter area and bite. I have been plagued with hypersensitivity, hyperpigmentation and extreme allergic itching to bites. Insects bite me even when doused with repellent, citronella candles and other repellents worn on myself. I'm just concerned that if bitten by a mosquito it might have been carrying a disease as I have never had a bite look like this before and I'm 51.  It does not look like Lime unless it is the beginning stages and the outer red ring hasn't formed yet.  I tend to not do the norm as far as medical books are concerned i.e. drugs that are "non drowsy" knock me out, ones that are "may cause drowsiness" wake me up, I don't anesthesize, etc... so I am worried this might be the case.  I got a bunch of flea bites while looking at houses 2 weeks ago but those healed but have been in the woods looking at houses the night this showed up.  We also have a horrible mosquito problem with huge ones that bombard you when you walk out the front door as well as come in and bite you loads of times.  Any help would be greatly appreciated in case I need to go to a doctor soon.  Thank you!