You are correct that you did NOT need to taper after just 3 days.

This certainly is odd that you had increased symptoms. I can understand if it didn't help, but to make it worse is strange. It may be that you just don't tolerate the medication/steroid...as in a type of allergic reaction.

I'm not sure I would eliminate the possible Dx of possible autoimmune cause. It could certainly mean that it is not, but the strange reaction to this may just be the medication, not anything to do with the root cause.