Hello thanks for consulting at hcm..
Since from a long time she is having these mouth ulcers, recurrence is the major factor,,earlier to the steroid treatment the ulcers were small in size, but post steroid treatment she is having large ulcers,, she is being resistant to the treatment..
You have not mentioned anything about the systemic health? is she diabetic, hypertensive, is she on long term medications for any disease??
Any preferred season or aggravating or relieving factors related to it..
She need complete blood tests, Culture sensitivity test and a consult with a gastroenterologist, allergy
specialist and oral physician,,
List of medicines what you have mentioned all all good, except the relapse following the stoppage of steroids
Take topical anesthetics, multivitamin
therapy, and add tbsp of baking soda to water,,dilute and use it as mouth wash.. It will reduce the pain..
Hope it helps,,take care..