I have been taking the medication for 21 days for lichen planus and it is in remission, can I reduce the dosage?

Patient.
The disease has been on for a long time, before and after four months, last month on the 6th to Qilu Hospital to let Professor Wang you treated, said that it is vesicular lichen planus; consultation when the whole oral mucosa erosion is more serious, now after 21 days of treatment, the condition has been alleviated, ulcers and erosion parts are reduced a lot.
The previous treatment at Qilu Hospital was basically ineffective!
I would like to know how to control the dosage of medicine now, today there is some discomfort in the stomach, I suspect that it is due to long-term medication, can the dosage of medicine be considered to reduce? Thanks a lot! Wang Weizhi, Department of Stomatology, Qilu Hospital, Shandong University