That was like the same treatment dermatologists gave me 3 years ago. Steroid cream after steroid cream. I used the strongest one, Clobetasol for 2 months with no results. Then I had a lip biopsy that explained nothing, and afterwards they wanted to inject steroids into my lips. I was like screw that and never went back.
It seems to be working for you though. Steroid creams never helped my lips. Hopefully it works for you. I also tried probiotics in the past with no results.