Suggest Treatment For Rash On Back And Chest

I have poison ivy it covered my back, chest, arms, ears, face, hair. I was given a shot of prednisone. then 5 mg of prednisone. 5 pills the first day, titrate to one in 5 days. Along with 2 benadryls every 6 hours and zyrtec. The rash went down a lil. But as soon as I quit taking the prednisone it seemed the rash got twice as bad. Went back to doc and got 10 mgs of prednisone, take 3 for 3 days, then 2 for 3 days, then one. The rash went away a lil more. Now it seems as if the rash may be coming back again. My question is will taking to small of a dose, or not taking the prednisone until the rash clears up. Will that cause the rash to come back?