Suggest Treatment For Rashes With Swelling As Benadryl Dint Work

I've had hives for about 2 weeks now. I've been to the doctor 3 times. The last time I went was a week ago and the hives have lessened into mild rashes. It still bothers me but there is no more swelling, only itchiness that comes and goes after about an hour then reappears somewhere else. The doctor did blood test and blood cultures and couldn't figure out what I was allergic to. They gave me an antibiotic shot that made the swelling go away, but the hives are mild but still present. I'm taking the antibiotic Cephalexin the doctor prescribed but I only have one pill left to go and the allergies still seem to be here. I use Caladryl as a topical solution but it's been a week since I started using it. I only take Benadryl before bed because it interferes with daytime activities. What do I do about the rashes? The doctor said I should be fine if I take Benadryl but it bothers me in the daytime. Is there another solution?