i would monitor the rash and if it appears to be getting worse -- warm to touch swollen or spreading -- you will need to go to the doctor for evaluation. since you are sensitive to these types of bites have you considered applying a topical product before you go out to avoid bites? there are a variety of different products on the market in various forms. there are even some sunscreens that now contain repellents.
there is a large rash on my leg after getting several mosquito bites. i am sensitive to bug bites - should i be worried?