My Baby Boy Is 4 Months Old. He Was Prescribed

My baby boy is 4 months old. He was prescribed with celestamine syrup 60ml last march 29. He was able to finish the dosage as per instructions by his pedia 3 days ago. His rashes were gone gradually but after stopping it went back yesterday. He finds it difficult to latch because of the itch. I wonder if i need to continue with celestamine? His pedia is out of town for a convention so i cant reach her