Thanks for query.
As you have thyroid
problem for last one year and you have this problem recently so any infection in the throat or viral infection should be ruled out.
I would suggest to go for one course of antibiotic before going for steroid
Do warm water gargles or Listerine
If you are going for steroid course, then what you have mentioned 10 gm,I think you mean to say 10 mg.
For going short steroid course,nothing to worry, there is no side effect.
As your doctor has advised go for tapering dose as advised by your doctor.
O and bye.