Will The Red Blotchy Hives Go Away Permanently With Prednisolone?

Two weeks ago I ate Smoked Oysters. Been eating them for years, at least one small can a month. I decided to go ahead and eat four cans within three days. Without checking for any green oysters I ate them all. About 24 hours later I started to get itchy on my neck and beard. Following day I had hives all over. They subsided at night, came back with a vengeance in the morning. I started to take Benadryl two days after the breakout. They don't itch since I started taking Benadryl, but they haven't completely gone away. Been to the ER twice and each time had doctors prescribe me to take Prednisone. I was directed to take 1 each day in the morning with food for 7 days. They started to go away until I stopped taking the steroids. They came back all over my body. Face, lips, feet, back, stomach, legs we covered. Hands were a bit swollen, so was my face. I was told my dose wasn't long enough. I was given 4 more prednisone to take. Right now I barely have any hives. Is it safe to continue taking the pills? will these hives go away? They appear as red blotchy, or sometimes small lines. Right now they aren't as inflamed, nor are there many. I'm just concerned about those horrible side-effects prednisone has.