Thanks for writing in.
I think the diagnosis in your case needs to be re evaluated.
does not last long and is treatable.
Now my advise to you would be-
You can use eumosone cream over the patch at night time.
Expose the affected area to early morning sunlight daily for 10 minutes every day.
Consider a visit to dermatologist
for prescription drugs and proper diagnosis.Skin biopsy
may be needed for exact diagnosis.
Hope this helps.