looks like bug bites Should i be running for blood tests?

I have what looks like bug bites all over my legs. Initially I thought they were mosquito or spider bites but I am not so sure. I have been to my dermatologist and thought that perhaps they were bed bugs. He explained that the rest of my family would be bitten up as well. I have checked my home, wash, clean, vacuum and still have what looks like bites. I do know that I am allergic to dust mites. At this point with all my research on the Internet, I have become fearful and have began to self diagnose myself with terrible things( hogkinns lymphoma). I've been trying to read up if the itchiness of that disease looks like the same as a "bite". At this point I have been using prescription cortisone to help for the itchiness. My Dermatologist recommends that I spray myself with OFF before I go to bed! Shouldni be running for blood tests?