Swollen columella

Hey, there! Could someone help me please? I have been experiencing a very annoying runny nose for about a month. Couple of days after it started, around 4-5 blisters developed in one of my nostril. I went to the ENT specialist, he said it could be an allergy. He also did some tests to check if there is an infection, but it came back negative. The doctor prescribed me the allergy medicaments and antibiotics cream. On the one side, I feel better as runny nose is gone, but one side of my columella is still swollen and I feel strong pain and burning sensantion there. Told my ENT specialist about persistent swelling, he told that it is strange as I am taking corticosteroids and said that now he is unsure what it could be. Any ideas? Or experiences?