I Have Dark Spots on my Leg when Bugs Bit Me They Become Water Bumps What is It?

when ever am in grass my skin itches and when an insect touch me my skin reacts strange it takes 30 seconds after contact with an insect for my skin to swell in large water bumps at that contact area.i am from jamaica now in florida looking for help my life has never been normal because of this ..i do not know what it is like to wear shorts nor walk on the beach all i need is to know what i can do to get rid of this skin problem help!