Benadryl ????????????????????

I was stung by a bee today and I am deathly allergic. Went to the ER today to get the Epi shot and an IV ran with other antihistamines to stop my tongue and throat swelling anymore. I was informed of relapse. The doctor put me on steroids and told me to take Benadryl every 7-8 hours. But, the problem is about 4 hours of taking 50mg I start breaking out in a hive all over my body again. Can you take Benadryl every 4 hours without any issue? I have put in a call to the hospital, but haven't got a call back from them yet. The hives are miserable. I appreciate all answers.