I went to San Jose del Cabo two years ago where I experienced what I thought was an insect bite on my lower arm. The area swelled slightly, itched and was pinkish. Most of the immediate symptoms disappeared, but the affected area has remained light pink and seems thinner than the surrounding skin. When it is exposed to sun, the area can become intensely pink to red, but is not swollen or burned and has no other symptoms. The area is about 1 x 1/2 inch in size with feathery edges. Can an insect cause this? Does this sound like skin atrophy? Any thoughts?